How do I wax chalk painted furniture to best protect it?

You can use furniture wax over the chalk paint. I like renaissance furniture wax - it is high quality. I apply it generously with a rag and buff it out with a soft cloth about 15 minutes later. Protects the furniture and enhances the paint color as well. Here is a link to the wax: https://amzn.to/2Bt9UpX

You can use dark wax or clear wax.Brands include- Minwax , Johnson’s, Brewax etc.To achieve Annie's signature look, apply a thin coat of wax over your painted surface with a small Chalk Paint® Wax Brush. Work in small areas at a time, wiping off any excess with a clean cloth. For a distressed look, sand back to reveal a little of the wood or paint underneath before applying a second coat of wax. I have used dark wax on dark furniture and clear on whites. Hope this helps.