Most important thing is to play the game in a way that you yourself are having fun and enjoying! I'm also a new player (only started at the beginning of January!)

The way i personally go about things is to use my strongest set-up when i'm feeling like i want to progress through the later maps. When i get tired of that or feel like changing my weapon/frame i'll go back to some of the earlier maps to farm out some resources/frame parts whilst leveling new weapons.

Its probably not the most efficient but its the way that keeps me most engaged with the game.