You can purchase supported decentralized assets (dToken) directly on Cake DeFi on your Balance Page by clicking "SWAP" on the right of the asset.
After that, a pop-up will appear and give you the option to SWAP/BUY that decentralized asset with other coins that you hold in your account.
You can also deposit and withdraw decentralized assets from and to a DeFiChain wallet by clicking on "Deposit" or "Withdraw".
More information on how to invest in and use decentralized assets on Cake DeFi can be found in this article.