Visit:
https://cloud.mathwallet.org
After finish log-in, click KSM to deposit more assets.
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You can also click Swap on the left to get more KSM.
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Then click Auction to participate in the Parachain Crowdloan.
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Take Karura as example, enter the amount of KSM for the crowdloan, start auction.
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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.