I want to be able to call makerDao’s Dai contract’s transfer method from my own contract. Does anyone know how I can get this done?

Import contract interface
Make a reference to actual dai contract using that interface
Call whichever method you want by using reference_variable.method()

Like Dai.trasferFrom()?

Yes

Assuming dai is a reference to actual contract

It should work with importing the Dai.sol file from GitHub right?

Theoretically, haven't worked with dai so don't know for sure

yes but you will have import problems when you will verify.
Anyway you should be able to use an IERC20 interface like this
IERC20 public token = token address

and then to use toke.transfer....

I suggest to add as welcome message lol

guys is there a way to charge BNB fees?

I think no because you can't control BNB balance right?