Issues with swapping ETH to BNB on Binance smart chain

Hello, I’m a complete newbie to this so I could be missing something simple, but I’m having trouble finding a way to transfer some ETH that I have on the smart chain to BNB tokens. I’m using metamask and can see that under the smart chain network I have the option to swap the eth however since my wallet only contains that I don’t have any way to cover the exchange fees as it seems they need to be in BNB. Is there something that I’m missing or do I need to find a way to deposit some through another means in order to complete the transaction? The reason I’m doing this is to use pancakeswap which seems to need some base of BNB tokens to do any transaction, but I could be wrong on this as well. Any help is very appreciated.