Every now and then the topic comes along about Plans-Scratch and Kit building. The purest will state a scratch build is when the builder designs his own plane and then builds from there own plans, OK, very true. I used to use the term Scratch/Plans when speaking of my own builds just to keep the purists happy. They are correct but I gave up saying it that way. As I kid I designed my own planes but today I just buy my plans and call it scratch building, sort of like baking a cake, I didn't grow the wheat or lay the eggs to bake from scratch.
If you haven't built a few, not just one but a few kits you may find even building from plans a bit daunting. If you buy plans from MAN or RCM they will come with the original building article from the magazine, sometimes these will even be of help. Most of my own planes have been built from plans. I buy my wood in bulk from Lone Star Balsa. My main tools are my scroll saw and belt sander. A good moto tool is always a help.
You may want to try building from a kit so you have a better idea of what the different parts are called and what types of glues and clamps you may need in a build.
If you really want to build from plans then look at the Model Airplane News Plans Service and buy a set for an easy build. The plans are numbered, a number 2 would be easy and a number 4 would be hard. They have a good selection of plans, so does RC Modeler. Plans will show the sizes and type of wood needed for all parts.