How can I add transaction fee to my bep20 token solidity?

I would like to add 15% transaction fee added to liquidity automaticaly.
How to add solidity

My code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.2;

import “Burn-it-up/BEP20Token.sol at cb70252eb67dc5bb953228f5a86bba14c3d0ad03 · panacompu/Burn-it-up · GitHub”;

contract CustomToken is BEP20Token {

constructor() {
_name = “Burn it up”;
_symbol = “BIP”;
_decimals = 18;
_totalSupply = 10000 * 10 ** 18;
_balances[msg.sender] = _totalSupply;

emit Transfer(address(0), msg.sender, _totalSupply);
}

}