however, missing the "how I do it" pics.
butt stock blank

because of my lack of experience I have to drill the 7mm receiver while the blank is still a squared blank


prepping for band saw


shaping on the band saw

rough cut butt stocks - all band saw cuts


drilling the fore stock  -  it's a piece of curly Koa




squaring up the fore stock


then comes the tedious sanding and fitting of the butt end to the pen receiver.  If you do it on the belt sander, you'll probably be making another one because you didn't pay attention and sanded too much off.  That's just an observation, I would never do that  myself.
Almost forgot, this is how I finish the butt stock.  I use a piece of dowel rod with a few wraps of tape and twist it into the 7mm receiver.  after I apply my finish I support the dowel in a hand clamp and let the piece dry.   This one is Rose wood

Then standard pen assembly is started and you end up something like this


I totally realize this tutorial does not meet your schooling standards but I'm just a beginner