From here click on any of the available markets based on the amount you are allowed to borrow and the borrow APY.
The WETH market is selected here. Choose how much of the asset you want to borrow based on the health factor of the loan. Borrower larger amounts of an asset with less collateral backing it makes it riskier and the opposite makes it safer (essentially less prone to liquidations given a certain amount of price movements in the borrowed/supplied asset). Press continue and borrow when ready.
Important: SPECIFICALLY FOR METAMASK you must set both the Max Priority Fee to 250 GWEI and the Max Fee to 250 GWEI or else your transactions will fail for borrow. Ignore the warning messages. This is not an issue for other wallets. Detailed below: