Converting token for payment in the background

[DorianDaSilva]

In the NFT Marketplace section of the course, Patrick suggests a challenge where we should write a code block allowing to convert any ERC20 token into ETH in the background as method of payment.

But I am not sure to understand how to do it.

How can I do the following:

1- Create a list of supported token for payment on the network
2- Automatically convert payments received in the supported token into ETH or any token I want (let's say a custom token X)
3- Complete the transaction using ETH or token X deposited

This is what it would look like:

User issues payment in supported token => supported token is then converted into payment token (ETH or token X) => NFT is purchased using ETH or token X converted => complete transaction

Any ideas on how to do this or suggestion of resources I can read/watch that will help me write this function?

Thank you!