Repainting aftermarket bumpers / step bars

I bought my wrangler in December and am using the summer to replace / modify it. It has aftermarket bumpers on the front and back. Metal and panted matte black. The paint is chipping on both and there might be a rust spot or two.

I have never done anything like this before but I am assuming the process is:

-Remove bumpers. -Sand Bumpers (or should I use paint remover first?) Also should I switch between sand paper grits to get paint off and then smooth the metal? -Paint bumpers -Reattach bumpers.

Any advice on the overall project from materials to use or even adjusting my overall step by step plan would be great! This is my first Wrangler and I would like to make most upgrades / modifications myself (AKA the easy stuff) and save the big ticket items that are very complicated for the mechanics (like updating any lift kit components. They mentioned my control arms should be replaced eventually, but ok for now.)