How to move ETH from Ethereum Mainnet to Rinkeby Test networks?


I was trying to move ETH from Ethereium Mainnet to SORA on Polkaswap Testnet and the Polkaswap Testnet is asking me to “Change the Network on Metamask” to accomplish my transfer. When I changed the network on Metamask to “Rinkeby Test” then Polkaswap Testnet said “insufficient funds”. So, I see that Polkaswap Testnet seems to be working with Rinkeby.

My ETH is on Etherium Mainnet and not on Rinkeby Test even though both the networks are on Metamask. I was under the impression that my ETH are in Metamask wallet and it shouldn’t matter whether I’m on which network within Metamask. As it’s proven it’s not the case I want to know how to move my ETH from Etherium Mainnet to Rinkeby Test network. Wish I could attach the screenshots here but I don’t see an option. Appreciate your response. Thanks much in advance.