How to use an Oracle to get a token value on Polygon? (Using web3.js)

Question

I'm currently developing a simple project. After a payment is done, I call a smart contract to mint some coins and send them to a wallet.

All good over there, but I need to know the value in USD of the payment done to know how much coins will I mint.

I'm currently working on the Mumbai Testnet, so my payment coin would be MATIC and the coin to mint would be This coin

I read about "aggregator interface v3" on this link:

Using web3js get coin price on uniswap and sushiswap exchange without using their api

However, I don't know exactly how to use it on my case. The example gets the price for ETH/USD pair on Kovan network, how do I get the address I would need to instanciate the aggregator for both Matic and the other coin? Would it work on Mumbai Testnet and/or Polygon Mainnet?

Of course, all this will be up on Polygon Mainnet so if the uses are different somehow, let me know!

Thanks for your time!