If you have to ask. My answer would be don’t try this at home, kids! Seriously, it’s a matter of having the right machinery, not just your typical auto tools.
If you know how or already disassembled the motor, take the head to a machine shop that specializes in rebuilds. It costs a bit, but it will save your sanity. This kind of work is done with micro measurements of 1/1000s of an inch, and requires the knowledge of using an a vertical end milling machine. The set-up is fairly technical.
you pull the engine out, tear it town and take the block into a machine shop to get it done, you simply do not have the tools needed.