Hi and welcome to the board!
Everyone has their own opinions on bedding and whatnot for their dogs, but IMO crate training works wonders for my two.
It is also a safe haven area for them when they want a break and just want to relax.
I would supervise any play behaviour between your puppy and your other dog. GSD pups are quite boisterous and I have an 8 month old who plays quite rough with my older girl so all play is supervised.
You will need boundaries as he will try and test you, he is only young after all.
Food is another issue, all depending what you want to feed him. Mine are on a raw diet but others may have a good quality kibble. It's whatever works for you and your dog obviously.
GSDs are highly intelligent so I would suggest some mental stimulating toys as well as chew toys. Not sure what type of toys you have over there so some other forum members may be able to help you with that.
Exercise is a must obviously, I take my boy on hikes already, he will stop when he is tired but as the saying goes "a tired dog is a good dog!"
I'm sure many others will help you with your questions and good luck with your new addition! Hope to see lots more pictures ^_^
Mum to 6 year old GSD Rescue Miss Jess and 8 month old GSD Loki