Add the Polygon network to the Metamask wallet

1)

2)

3)

4)

5)

Network Name: Polygon Mainnet

RPC Url: https://polygon-rpc.com/

Chain ID: 137

Symbol: MATIC

Block Explorer URL: https://polygonscan.com/

6)

7) Go back to the NFT purchase instructions; go to clause #3.

https://telegra.ph/How-to-buy-NFT-using-a-smartphone-07-02