This walkthrough will go over the minimal steps to execute a standard trade.
Navigate to https://app.balancer.fi/#/trade
(We're using MetaMask in this example)
Click one of the "Connect wallet" buttons, click MetaMask, and connect your desired wallet in the extension popup.
You can specify either an input amount or an output amount. In this example, we've entered an input amount.
Approving your token will issue an Ethereum transaction that will have a gas cost. This is not paying a fee for your trade; you will need to issue another transaction.
Click swap and approve the transaction in MetaMask.