Ah a tumbler compost bin... personally having used one when we had a large veg garden I wouldn't recommend and neither does Which:

http://www.which.co.uk/news/2011/07/compost-tumblers-a-revolution-in-recycling-garden-waste-258851/

Just use a normal compost bin, much easier and you are less likely to do your back in!

You have been given it so just give it a go. Give it a spin every time you pass it.

They are designed to avoid the need to keep turning the compost. It would be interesting to hear how you get on with it and how effective it turns out to be!

Ok. Will give it a go. Anything I should or should put into it?

Personally I think they are a waste of time, it looks like you have two good wooden compost bins there, I have been making compost all my life, it's very simple, the only thing to remember is to make sure you got enough stuff to compost, grass cuttings, leaves, veg peelings etc, it's surprising how quick the compost heap goes down so keep filling it, next year use the other compost area.

don't put any cooked food waste in as it will attract vermin.
add newspaper too if they mix is too wet. I also add the sawdust from the gerbil when it gets cleaned out.

Agree with Julien waste of time, we never turn our compost just let it get on and do its own thing - that's why you have more than one bin. I tried turning the tumbler composter when we had it and found it extremely difficult because of the weight... certainly couldn't turn at all now.