Welcome. Disassembling Timex watches is not recommended for a beginner, because it requires re-assembly, which is not easy or conventiona. You will find some reasoning on why in the below, and in various more discussions.
When it's about servicing low material value watches, the first question should be "is that really necessary?". If it does not keep good time, an attempt to demagnetize and regulate should be made first. Since the "right" tools and environment to do that "almost professionally" can set one off €200 easily, that sets things in perspective I think.