I kept on re-reading the RSTS/E BASIC PLUS language manual until it made sense. I remember DIM statements being the hardest thing to figure out.

I didn't either as a kid. I had one of those British Usborne Publishing computer books - one of their intros involved paper only with a long roll of instructions you wrote out and pulled through a cardboard "window" for the current instruction while you kept track of variables on a sheet of paper.

I soon figured out you didn't really need the roll and cardboard window, and could just do the while thing on normal sheets of paper.

Got to try it out for real on a borrowed TRS80 not too long after that though.