>>28754145Play the third edition of every game. Start with Fire Red/Leaf Green, then play Emerald, move to HeartGold/SoulSilver, then play Platinum.
With B/W and B2/W2 you can play both because they're actually different games, albeit taking place in the same region. You even explore areas that weren't in one another and vice versa.
Then play X/Y. Play the remakes of Gen 3 at your own peril.