Reddit reviews The Materials of the Artist and Their Use in Painting: With Notes on the Techniques of the Old Masters, Revised Edition

I have a brief amount of time so here's the short and skinny. You can use any colors you want, but traditionally you'd use primarily earth tones for the underpainting. Try this approach: stain the canvas with yellow ochre thinned with turpenoid/gamsol. Use a rag or cotton swabs to pull back out the light areas. Let that dry a bit, then continue with a value study using burnt/raw sienna and burnt umber. No need for white yet, just use the raw canvas. At this point you'll only want to be using thinner as your medium. When finished let it sit for a day or two to dry.

Now you may proceed with oil as your medium. You'll want to use more transparent pigments mixed with linseed/walnut oil to create glazes. Work in layers allowing time to dry in between. Don not varnish between layers. And more oil to your paints as you build up layers. Thick over thin process is to prevent cracking.

Good luck. Experiment. See what works for you. Look up artist handbooks on techniques. This one is generally considered the painter's bible.