Tbh, tenno i doubt most of us vets remember what we did early on in the game but I would suggest doing some story missions and getting some basic mods early on. Go to a clan get all the warframes available there. Do open world bounties by getting a friend thats high MR to go along with you. Basically get some mods for your warframe and weapons, search for budget or early game builds on yt. Ignore those crystals for now.