I will share how I made a wood picture plaque at TechShop - www.techshop.ws
Step 1: Jointer / Planer to Smooth Rough Cut Wood
Starting with a rough cut piece of wood, which is less expensive, use the Jointer to smooth out one side. Use paddles to safely move the material over the blade. Don't cut more than 1/16 of an inch at a time.
Once one side is at least semi-smooth, the wood can then be placed in the Planer to finish both sides. Once the machine starts biting into the wood, continue running it through the planer one side at a time rotating it with each pass. After each pass, the wheel can be turned 1/4 rotation to smooth the surface deeper and deeper.
After both sides are smooth, or to the desired dimension, the Jointer can again be used to smooth all four sides.