First, you need to have wallet that have Lightning Address and Zaps (NIP-57) support. If you are not familiar, you can start with custodial wallet like Wallet of Satoshi

https://www.walletofsatoshi.com/

or ln.tips telegram bot.

Next time after you become familiar, you can change your wallet into Non-Custodial Wallet like Phoenix, Breez, Blixt, etc.

Copy your LN address from Wallet of Satoshi and paste it into your Nostr profile.