If you don't have a Fearless Wallet, feel free to download it:
Once Fearless Wallet is installed, open the app and Create/Import an account. For Importing an account, you can use the mnemonic phrase/seed or restore JSON from another app/mobile wallet.
Tap on “Crowdloan '' at the bottom of the app, select “Shiden” in the list of the Crowdloans, and enter the desired amount you wish to contribute.
Review information such as potential reward in SDN tokens, fees for the operation, leasing period. You can also visit Shiden’s page to view the details of Shiden’s Crowdloan campaign.
Press continue and review once again the details on the confirmation screen. Once that is done, tap: Confirm and that’s it!