How do liquidity pool fees work?

The fee you'll get depends on the percentage of your deposit in relation to the pool. In simpler words, if the pool has $900, and you deposited $100 (bringing it up to $1,000), you'll earn 10% of the fees. Every time someone uses the pool for swaps, you'll get a small percentage as a reward, since you're a liquidity provider to the pool. So, liquidity pools' fees are split appropriately based on the liquidity provider's contribution.