I need help getting back into vanguard

ok so, I used to play the game alot back in the day, like back when it was first coming out, but was a broken student and eventually stopped, as you can imagine im very much out of the loop.

I cant make heads or tails of all the new stuff, bind stuff, new types of skills, stride, etc, and most confusing of all, the names/numbers of the boxes. (DZ-VGE- something?)

now i want to build a couple of Keter Sanctuary decks, but holy shit, I guess cause only 5 nations, each one has quite a number of deck builds.

for keter im seeing Rezael and Luard mentioned alot, should I aim to build decks for them? or are they outdated and I should go for something else?

im so lost and some guidelines would really be appreciated.