Forgive me, I am not handy...

I have a lightweight hunter and I want to switch it to a Apex stock - has the lop inserts. I thought this would be a simple swap with my existing hardware but it is not.

The wood stock has an open channel between the magazine and trigger guard area. This synthetic stock is solid between.

What parts do I need to use the axis style mag? After searching and looking at parts, I remain lost.

Thank you