Select FTM on the left/top (token to be swapped) and COMB on the right/bottom (token you are swapping into)
Enter either the qty of COMB you want to receive, or the qty of FTM you want to exchange.
Click the Swap Button then approve in MetaMask (NOTE: Leave a small amount of FTM in your wallet (1-2 FTM) to cover future fees)