There was a lot of standing around involved as you had to be there to cover the possibility of someone needing help. When you stand around in a high visibility vest you get a lot of people assuming you know everything about the event so we often learnt the layout of the venue so that we could direct people to where they wanted to go!!!
You have to be willing to deal with whatever arrives. So everything from a sticking plaster to someone who needs an emergency ambulance and their panicking relatives. You are never on duty alone though so you do have support. You also have to be good at hiding your feelings and trying to look like you are very calm and know exactly what you are doing. That bit I was quite good at as I have spent a lifetime being able to hide my real thoughts and saying what I have learnt I should say. But can you imagine someone appearing with a bone sticking out of their leg and saying "****(&*^, that looks horrible". No, you had to show a reaction more along the lines of "oh we do this all the time, you're in good hands". I learnt a few stock phrases as I find it difficult to know how to reassure people. How I gain reassurance does not always seem to be the way some other people gain reassurance. But I was able to learn a few of the 'right' things to say to get me through that bit.I think it's great that you are interested and considering doing a one day course. Even if you remember just one thing from it then it will be worth doing. Actually one of the best things that anyone can do in first aid is just to be with the person whilst more help arrives so they know they are not alone. Reassure that help is on it's way and that you won't leave them until help arrives. That kind of thing. But of course being able to put someone in the recovery position and having a bit of experience of CPR is also good.
Whilst there is theory to learn I've found that the first aid courses tend to focus on the practical as that is important. So if you learn well by doing things then it's a great course for you.
I did enjoy the volunteering in some ways but in other ways I didn't.
It gave me the confidence to help others even if I wasn't on duty. I remember being a passer-by at a road accident where a teenage girl had been hit by a car and was barely conscious. Someone had already rang the emergency services but there were a lot of people standing around whaling and looking confused. I sat with the girl, held her hand, asked one of her family members to keep talking soothingly to her and monitored her vital signs until an ambulance arrived. The first ambulance that arrived was actually a PTA (patient transport ambulance) so the guy from that just walked around with a clipboard. I asked him to take over and he said he couldn't as he wasn't trained for first aid!!! So I had to wait for the next ambulance which was the first responders. They walked around a lot whilst I stayed sat with the girl monitoring her vital signs without them even asking me anything, presumably because they could see I had it under control. Eventually an ambulance arrived and they finally took over from me. It was me that had spent all that time with the girl and her family reassuring them that she'd be ok. Once I was released from her I went to speak to the driver of the car to check she was ok as everyone seemingly had forgotten about her (she was ok but understandably in shock).
It might not sound a lot but it meant that that the whole situation had been calmed down so by the time the ambulance and police arrived they could get straight onto their jobs. Bit of a thankless task except for one person who had observed it all and came and thanked me afterwards as they had realised how the things I had done had helped the situation. It was really nice that someone noticed and bothered to comment on it.
But in the voluntary role, there was an awful lot of moaning from the other volunteers about the processes or about other volunteers. Much like you can find in any workplace. I prefer to see the good in people or to understand the point of the processes and try to just get on with things, but the politics was so draining.
I found the usual thing that if I tried to talk about anything else (such as people's other interests or music or such) that no one was interested and everyone wanted to continue moaning about a particular person who had said something to someone that really didn't matter that much. In the end I had several reasons I didn't want to continue with it, but the perpetual moaning was a reason that I didn't give when I resigned. I didn't want to burn my bridges.
Rest assured that on your lunch break on your one day course there will be an opportunity to busy yourself with something. You should receive a first aid manual so you can definitely spend time flicking through that. If you've already done some practical stuff in the morning the dummies might be left out and you can get a bit more practice on them. If you do feel like talking to someone there should be plenty of material about first aid and how the morning went to be able to have some common ground with the others in the group.
If you get on the course and hate it then you can just tell the tutor that it's not what you thought it was and that you don't wish to continue with it and leave. As long as you explain that to them they're not going to have a problem. It's a voluntary course and first aid isn't for everyone. My husbands faints at the sight of blood or with particular injuries. I once had to take him to hospital, not because of the injury to his foot that he had got but because he looked at it, fainted, banged his head and broke his nose!!!
The assurance is to keep them and the bystanders as calm as possible. You probably want them to stay still, particularly if there could be a neck or spinal injury. If they start panicking then they'll want to move around and this could cause more injury.
If you can give an appearance of calm with you and the injured person then it becomes easier to also calm down the people around you. You can find that family members or bystanders become panicky (understandably) and it is a lot easier if everyone can remain as calm as possible.
You're right that the heart rate can go up too and it's preferable to keep that beating as normally as possible. Similarly to keep breathing as steady as possible. If someone is bleeding then you need to stop the bleeding as quickly as possible and you certainly don't want a heart pumping blood around even faster.