A guide really isn't necessary for the first part of this game. The hard part is just figuring out which way to go. So here's map detailing the layout of the area, where to go, and exact instructions of what to do and what order you need to do them in.

https://www.gamefaqs.com/nes/587514-platoon/faqs/73150?raw=1

All credits of this map goes to StarFighter76