Okay, so here's the best I can recommend for you if you want to save your shards and whatnot for events.  It can be done.  Just by playing the campaign, you can level up your champs.  Take your starter, and whatever random champs you have that you don't care about...mostly green uncommons.  Play the campaign as far as you can with who you have.  Once your uncommon reaches level 20, use two uncommons that you haven't touched to make them a 3*.  Do it again, and again... and again, until your starter is a 6* level 60.  If I remember correctly you'll pull Warpriest fairly early.  Ascend your starter, give him/her max Masteries and Tomes (commonly referred to here as books).  These champs you are levelling up only to sacrifice to level another champ are called chickens or food.  Use your warpriest as support until something better comes along.  Do not ascend or book warpriest.  This uses up vital resources that will be better spent elsewhere.  Side note:  DO NOT USE ARMIGER OR SAURUS AS FOOD.  These are Epic champs disguised as Uncommons.  Saurus is great for campaign farming (What I described earlier), and Armiger has two outstanding skills.  Once you have an Armiger fully booked and a Saurus fully booked (skills maxed out), then you can use them as food.  Just keep making Uncommons into 5*, level 1.  Eventually you'll find many Rares that aren't worth the effort or resources, and they will become food.  Or you'll grind one location and have tons of Diabolists or Hound Spawn that you can use as food.  Also, your gear for your starter should be at level 16 and enchanted as soon as possible. I hope this helps.  It's a lot, but you asked.