Help mounting a live edge table

Hi r/woodworking

I was gifted an 8ft long by 2ft wide maple slab from a friend who was closing his furniture shop.

I am mounting this on an old 60’a style indoor concrete planter. It seems like it’s slightly warped so I think I need to shim it and attach it to the planter somehow. I also want to keep it from warping further and have read about adding c channels to the bottom.

I am handy and have some tools but this is outside of anything I’ve done before. Any help or advice would be greatly appreciated!