Overview
I made this guide to try help new players.
First step
I´m a new player. Just choose 3 beginner robots. So now what?
Don´t jump to PVP as soon as you start. You shall get beaten senseless only.
The first step is to do all the “Mate” 3 Guardians quest line first. They are easy to do. Just press F1 then Mates and start the quest. To do the tunning part, just enter Chaos battle a couple of times and after some battles buy the 10 cost weapon with walk and tune walk +1 in the 3 slots. You should have gotten a robot with 21 walk by then and just equip it with the weapon to get 25 walk (next part of the quest). With this you should get tons of tunning material. BUT don´t tune robots yet. Do all 3 guardians quest line.
After then you should start getting more robots. There are others guides about coins and robots so i won´t mention much about then here. There are a lot of good and free things to farm and some are easy to get and some are not so easy to get like farming raid bosses. Some robots that are easy to get and that i personally like:
Ouka – Go in the Angel Force base and do the Scarlet Moon mission. An easy way to get her is just junk your robots and rebuild then. You get her after 15 medals.
Seraph Crimrose – There are others guides for this but a fast hint here is grind Chaos room for Angel coins. Buy present and give to Crimrose in central area to get her present back. Rarely it gives you a Seraph promotion. Just make sure to lv 10 Crimrose before promote her (at least before it should be done or she would lose stats).
Gyallanbard – You get it from Robo cube. Buy it with angel coins.
Lancerlot – Grind mission coins to get entrys to farm Berzellius. Find a good team to farm it 2~3*.
After you get some robots you should have some that you like. NOW is the time to fully tune 1~3 robots. My only suggestion here is to remember to have a good amount of Run or Fly.
Only after max leveling (use tickets really!) the robots and fully tunning then you should go to PVP.