First, determine how much collateral (e.g. ETH) you want to lock up in a Collateralized Loan. Then, you can borrow the asset (e.g. DAI, USDC) against the collateral you locked up, and spend them as you like. Payback your loan (e.g. DAI, USDC) when you no longer need the liquidity, together with interest accrued. Paying back your loan allows you to withdraw the collateral you locked up.