In the beginning you would only need to generate some receive addresses in order to receive money to your wallet once they are mined. The money transfer in the cryptocurrency network goes from one address to another. You could generate as many addresses as you like.
Keeping different addresses for different sources is good, because you can see where money come from. To make it even simpler wallet lets you label particular address. Just go to your wallet and press "Receive" button. On the bottom you would see the a New Address button. Press that and new address will be generated. You will be also prompted to add a label.
Basically you can generate as many addresses as you like. However the following should be taken into account when you backup your wallet.
NB! Your wallet.dat file keeps next 100 future addresses in it. This means that if you backed up your wallet and generated 101 address since then, the money you will send to 101 address will not be visible in your backed up wallet. In other words if you by any reason decide to restore the old backed up wallet, the 101 address and all the money associated with it will be lost forever. Do your backup more or less frequently!
Useful links:
NB! Your wallet.dat file keeps next 100 future addresses in it. This means that if you backed up your wallet and generated 101 address since then, the money you will send to 101 address will not be visible in your backed up wallet. In other words if you by any reason decide to restore the old backed up wallet, the 101 address and all the money associated with it will be lost forever. Do your backup more or less frequently!
Useful links: