To add liquidity to an AMM like UNI you will need 2 assets in a 50/50 split in terms of dollar value and some ETH for gas fees.
Select which token pair you want to add liquidity for
Fill in the amounts you want to add to the liquidity pool.
It may ask you to Approve the tokens - you will have to send these "approve transactions" first.
Once you've approved the token you can hit Supply
The transaction will provide you with some UNI-V2 LP tokens in your wallet. These are Uniswap LP tokens and represent the share you've deposited in the pool. All pools are labeled as UNI-V2 LP but represent different pools.
Once you have added liquidity to Uniswap you are ready to Stake on Bao.finance