1) Go to the Mint kUSD tab. Go to the Vault you'd like to interact with and click Manage.
2) Users that are interested in paying back their kUSD should select Pay back and enter the amount of kUSD they'd like to pay.
Users interested in minting more kUSD should select Mint More and enter the amount of kUSD they'd like to mint. These users should note the New Collateral Ratio and New Liquidation Price.
Users interested in depositing additional collateral should select Deposit and enter the amount of collateral they'd like to deposit.
Users interested in withdrawing their collateral should select Withdraw and enter the amount of collateral they'd like to withdraw. These users should note how the withdrawal affects their Collateral Ratio and Liquidation Ratio.