you have to download the wallet through the coins official website. You'll need a separate wallet for each coin you need to store. In the event youre just planning to trade them for other coins, you can store them around the exchange wallet associated with your account. Every coin has it own blockchain (don concern yourself with being aware of what a side chain is appropriate now while youll probably get confused in case your-centre new to everything at this time) every blockchain has addresses related to it that arent linked to other blockchains. This can be why you ought to have separate wallets to the addresses to the coins youre storing in it.