You must first enter the SeaSwap DEX

SeaSwap Exchange
SeaSwap is a fork of the Uniswap protocol for exchanging ERC-20 tokens. It eliminates trusted intermediaries and unnecessary forms of rent extraction, allowing for fast, efficient trading.

You must click on: Connect to a wallet

A window will open, in which you can see the compatible wallets and select the one of your preference.

and that's it! you already have your wallet connected.