I have some ETH from Uniswap. I see there’s ETH as well when I switch the network to BSC for pancake but it shows up as zero. If I convert them in BNB in Uniswap will they automatically appear when I switch to BNC/Pancake. I don’t understand how eventually sending them will help, my address on both network is the same, it feel like sending stuff from and to the same address:
0xDB641E044f7849166B86ee37652C3B84eB2E7192
Any idea? I think I’m missing something:)
Thank you
Welcome to the MetaMask Community @horizonrave!! 
The Binance SmartChain (BSC) is a fork of the Ethereum Mainnet. This means you can use the same address to send and receive tokens on both networks, but tokens that are on one network are not available on the other network.
If you want to convert your ETH on the Ethereum Mainnet to BNB, you will first need to use the Binance Bridge to transfer your ETH to the BSC. Your tokens will then become a pegged ETH token on the BSC.
You can then swap your pegged ETH tokens to BNB using the swap function on MetaMask or third party like PancakeSwap (Uniswap does not support swaps on BSC).