How to work out which componants I can fit! (chain)

[bobbledash]

Sos to dive in with the newb question! Hopefully I will contribute less needy posts in future.

I can't seem to find a list of components for my bike anywhere.

I have a 2017 Trek Powerfly hardtail 4 17.5 inch.

Main problem is I just snapped the chain - looking at decathlon, how do I work out which one to buy.

I also want to fit fatter tyres for sandy conditions. How do I go about figuring out how far I can push it? Do I need new wheels too?

Thanks in advance.

 

[Jackware]

You need to buy a chain that matches the number of cogs on the back wheel, so 9 cogs on the back equals a nine speed chain. The brands ie Shimano, Sram KMC are interchangeable but different people have different preferences and whole threads are taken up with people claiming how great their particular choice may be
You'll also need a chain tool to split the new chain to adjust itss length to that of the original. There are plenty of YT videos showing that process.

So people can advise on the tyres can you provide any wheel size info from the rims and what tyres are you using currently?