transform.InverseTransformDirection in Tiny?

How do you convert keyboard Input to a player's local direction for movement? For example, moveDirection.z needs to line up with a player's local forward direction. I read you can use LocaltoWorld but I need help on how to use it. There aren't much example I can find online. I found this thread, but I need help understanding it to see if it's relevant or not.
https://forum.unity.com/threads/transform-inversetransformdirection-for-ecs.652543/

Below is an example of what I want in OOP.

Code (CSharp):

1.     // convert the world relative moveInput vector into a local-relative
2.             // turn amount and forward amount required to head in the desired
3.             // direction.
4.             if (moveDirection.magnitude > 1f) moveDirection.Normalize();
5.  
6.             moveDirection = transform.InverseTransformDirection(moveDirection);
7.  
8.             moveDirection = Vector3.ProjectOnPlane(moveDirection, m_GroundNormal);
9.             m_TurnAmount = Mathf.Atan2(moveDirection.x, moveDirection.z);
10.             m_ForwardAmount = moveDirection.z;

 

Great! I got the player moving with keyboards by using the Update function linked above. I started off my project by modifying TinyPhysics, which I thought was a closest template for my third person player project. But it turns out that TinyRacing's method works better for what I needed. Thanks