Visit:
https://cloud.mathwallet.org
After finish log-in, click KSM to deposit more assets.
You can also click Swap on the left to get more KSM.
Then click Auction to participate in the Parachain Crowdloan.
Take Karura as example, enter the amount of KSM for the crowdloan, start auction.
Note: The amount of rewards and lock-up time obtained by staking KSM is determined by the project itself. You can click More Project Information to check for details; KSM will be automatically refunded to the cloud wallet after unstaking.