Just a lost Tenno, seeking a little Guidance

[(PSN)Juicyington]

Hello!

I started playing Warframe around the time Nekros was introduced. My friends and I took a large break from the game, but have eagerly returned... Only to be completely lost. I'm looking for a guide, so that I can understand all the change that I see. 

Thanks in advance!

Psn: Juicyington

[(XBOX)LTK FIRE]

Void keys got reworked and now they are relics, you farm relics the same as you did keys. You can refine them to have a better chance at rarer items. But each time you use a relic its gone. Meaning how we used to have tower survival keys that used just one key now its 1 relic a rotation. Also the star chart has been reworked, to unlock planets/quests you have to complete junctions. Most planets have junctions besides the Void. Also we have melee weapons from syndicates for 125000 standing. Vacuum  has been allowed for every sentinel.