The first thing to do is to take some pieces of plywood and to then go on and make markings on them to the size of each panel that you would want to use.
You can then take some chalk and draw out the lines of the panels, making sure that each panel is the same size. However, if you need some special sized panels for specific areas, you should make measurements for those as well.
You now need to go on and cut out some decorative molding that you would be applying to your panels. Make sure you get the dimensions right while cutting it out, or you could end up having some problems later on.
Next up, you need to go on and attach the moldings individually to each piece of paneling. Make sure you secure the molding on the panels via nails and then fill out the holes with fillers, paint or putty.
Repeat the last two steps till you have enough panels with moldings attached to them.
Paint or decorate
The next thing to do is to go on and paint the wall panels. You may do as you please with them in order to make them stand out or suit your need.
Attach to walls
Next you need to find and locate all the studs in the wall. After you have done this, go on and attach the panel to the walls, making sure that you keep in mind the location of the wall studs.
After doing so, attach the panels to the wall via nails.
Finish up by scraping off any rough edges and filling in any areas that you feel need more smoothening.