At https://app.dyadstable.xyz/, Note owners can deposit collateral after connecting their wallet, navigating to the 'Deposit & Withdraw' tab and selecting their preferred collateral type (up to 5 different collateral types at one time per Note).
In case no collateral was previously added, click on one of the empty fields to add one of the supported collateral types to your note.
After adding a collateral type to your note, you can proceed to deposit collateral. Click Approve to review & confirm the transaction in your wallet.