I used the factory contract to create the pair contract, how do I get an instance of the pair contract in Hardhat. Used to query the LP value of an account
The title of the question and the content is far different.
If you're using the factory, then there's a function getPair, which returns you the address of the pair.
function getPair(address tokenA, address tokenB) external view returns (address pair);
When you have the pair address, you can fetch the number of tokens in the pair using getReserve function