Once your token migration is complete you can choose whether to add liquidity for the pair yourself, or if you'd like to start a public presale in order to gather liquidity using the power and funds of your own community.
if you'd like to add your own liquidity, first click, one at a time, the "approve fBNB" button and then "approve your-token-name" button and confirm the gas fees dialog for each.
Once that's done the two "approve" buttons will be replaced by one button called "deploy swap".
Now you can input the token amounts which you'd like to add as liquidity for both your token and fBNB/fETH and click the "deploy swap" button to finish.