For everyone
Get a Solana wallet for P2P
Buyers need a wallet that can send SOL. Sellers receive net SOL on settle.
Install a wallet you control
Phantom is a common choice. Install it from the official site, write the seed offline, and copy only the public address when a screen asks for one.
P2P buyers send SOL to the treasury. That is different from pasting an address on Econext Wallet for a cash-out.
Keep the two identities separate
credentials.json is the Agent Play node. The Solana wallet is the chain account. Losing either is a loss we cannot reverse.
Read How it works and the Terms of Service before the first send.