This probably doesn't need a guide....
You collect techscrap by killing enemies (or as a reward for completing quests or find piles and caches while you explore the world). At Med Bays you can spend the techscrap to increase core power. Each new level costs more than the previous one.
You will get this achievement sooner or later, because increasing core power is a crucial thing for progressing in the game.
Most likely you will unlock it not long after killing Little Johnny (the first major boss) and Brother Eli in Port Nixon. There will be more areas to explore and more enemies with better scrap reward to kill.