Install MetaMask from the official website, create a new wallet and secure the seed phrase, then transfer ETH to your MetaMask address to buy a token on Ethereum.

Connect to a DEX like Uniswap, SushiSwap, or 1inch. Open the DEX website, click 'Connect Wallet', and select MetaMask. Approve in MetaMask to trade.

Select ETH in the 'from' field and your desired token in the 'to' field. Enter the amount, click 'Swap' or 'Exchange,' and confirm in MetaMask

Check your transaction status in MetaMask under 'Activity' or on Etherscan. If the token isn't visible, click 'Assets,', 'Add Token', and enter the contract address.