BEP20 tokens are just tokens on the Binance Smart Chain.
You can use decentralized exchanges like Pancakeswap to trade any BEP20 token.
On Pancakeswap, you have to use BNB (Binance Coin) to exchange and trade BEP20 tokens.
To fund your Binance Smart Chain wallet with BNB, you can use the Rubic exchange to swap Ethereum tokens on the Ethereum blockchain for BNB on the Binance Smart Chain, which gets deposited into your Binance Smart Chain wallet.
Another way to fund your Binance Smart Chain wallet with BNB is through centralized exchanges, like Binance, Kucoin, Coinbase, etc, where you buy BNB on the exchange, then just withdraw to your Binance Smart Chain wallet.
To view information about a specific BEP20 token, you can use Poocoin to view charts, holders, liquidity and any recent trades.
The most popular Binanace Smart Chain wallet is MetaMask (MetaMask supports almost all blockchains).
Binance Smart Chain is a centralized blockchain operated by Binance, with the fees being a few dollars each transactions and the transactions being almost instant. Ethereum on the other hand currently has fees in the $120+ range and it takes a little while for transactions to be confirmed.