I am not sure I fully understand your question, but I can certainly tell you what the difference is between those three German words:
1) die Anweisung = the order/ instruction, e.g. "Er gab ihm die Anweisung, das Tor um 18 Uhr zu schließen.". (He gave him the order to close the gate at 6pm.) or "Folgen Sie bitte den Anweisungen!" (Please, follow the instructions.)
2) der Vorschlag = the suggestion, e.g. "Kann ich einen Vorschlag machen?" (Can I make a suggestion?")
3) die Anleitung = instructions in a manual explaining how something is done (even though the German word is a singular, but that happens quite frequently that English uses a plural noun while German uses a singular noun for the same item, such as pants/ die Hose, glasses/ die Brille), e.g. "Der IKEA Schrank kam mit einer praktischen Anleitung wie man ihn zusammenbaut." (The IKEA closet came with practical instructions on how to assemble it.)
If you need any more help with German or translations, feel free to contact me through WyzAnt or find me online: Renata Urban Training. I am a bi-lingual, trained, and experienced language instructor, intercultural trainer, and communication skills coach.
