When you are solo mining you are looking for entire blocks. If you are lucky to find one the block will be deposited right into your wallet. When you are pool mining you are working together with the pool. when a block is found the coins are divided up amongst the pool based on how much work each miner did. Pools will find more blocks so even though you only get a small share you will get much more of them. You should theoretically get the same amount of coins over time either way. You can get lucky when solo mining and get more coins but you can also go long periods of time without finding anything. If you don't have the correct settings for your miner you likely will never find anything.
Pools guarantee a set amount of coins based on how much work you do. They are also much easier to use as you dont even have to have a wallet. You can set the pool to payout your earnings directly to an exchange. This equates to more fees and is less secure. It is always a god idea to store coins in a local wallet and keep only what you are willing to lose on an exchange if you are not actively trading at the moment.
My tutorial goes over most of this and more content will be added soon