predmarket runs on Solana devnet. You need a wallet, a little devnet SOL for fees, and devnet USDC to stake. All free, all valueless — this is a test network.
Get Phantom or Solflare, create a wallet, then switch its network to Devnet in settings.
Phantom ↗ Solflare ↗Paste your wallet address into the Solana faucet to receive devnet SOL for transaction fees.
Solana devnet faucet ↗Use Circle's testnet faucet, select Solana Devnet, and send test USDC to your wallet address. This is the token you stake with.
Circle USDC faucet ↗