Deploy a new UniswapV2-style pair on Monad Testnet and seed it with your initial liquidity in one transaction. Paste any two ERC-20 addresses (or pick a core token), set the amounts, approve, and add liquidity. You receive LP tokens representing your share of the pool.
Pools are permissionless: anyone can create any pair. PuddleSwap is unaudited; use at your own risk on testnet only.