ok Im in training camp for the next few days. What am I supposed to be doing during this time?

Preparing to cry when all your high picks bust. Other than that, you don't need to do anything.

also training camp runs over a single sim then you go into late FA

Check that:

Late FA .. Training Camp .. PreSeason ...

So the answer is 'nothing'?

Yes .. After the training camp sims you will see how your team start to trend. Vets may begin their decline and rookies will either show if they are going to booms or busts..

You can take 60 players into camp. If you want to. Staying at the 53 is ok too.

You also have to have a minimum of 45 players. If you have less the AI will sign someone for you to get you up to 45.

It's not advisable though. It used to be that players would not get a boost if they were not on a team at the start of training camp. I think that JDB has changed this, but I'm not sure if it's rolled out to all leagues.

I play all 60 to have the option to reduce injuries.