E&P rooster is a pyramid where 5* are on top, 4* in the middle and 3* as it’s base.
Try to keep every copy of each hero, it’ll be useful for game formats wich would require certain elements or classes. Complete events and quests that gives you ascension materials, emblems and aethers and stack coins for when you’ll be able to ascend 5*.
Expand the heroes’ rooster when needed and play the waiting game: unless you want to spend to get materials, most of the heroes you will get as low level player would get better versions of them under the form of costumes, will be overshined by newer released ones or hopefully being grouped together in a portal.
Check on the forum good upconing heroes of the month or seasonal heroes to target with your hepic hero tokens and use your epic troop tokens when special troop portals appears, the most prized ones are with mana generation.
For raids don’t worry, to do well you should level up your heroes and bring the right ones to counter your opponents.
To know more I would start taking a look here Master List of E&P Links & Player Guides