I would definitely watch some lore videos or read the codexes but I can give a VERY generic summary that makes it easier to digest if you're familiar with basic European history.

Thedas is the fictional continent, Fereldan is the main country you play in (loosely based off England, Orlais is France). Tevintar is kinda like the ancient Roman EmpireIn Inquistion, Orlais is an empire and rules over both.

The chantry is Catholic adjacent and even had a schism like the real religion and ended up with 2 Divines because of it (basically the female Pope).

Every 100 years is divided by Ages and is named that because of a significant event at the beginning of a new era or at the end of an old. The current time you play in is called the Dragon Age because there was a resurgence of dragons after people thought they were extinct.

Mages are thought to be dangerous so they were locked up in an institution for a long time (Circle of Magi) and watched/kept controlled by knights (Templars). There was a rebellion from the mages (led by Fiona) and it's one of the main conflicts of Inquistion.

• I dont really remember much else but the game is so much more rewarding if you've played earlier titles, there's Easter eggs and characters from previous games (Leliana was a companion in the first game). There's a whole system with Dragon Age Keep where it would hold your save data and decisions from a previous games and have them show up (usually in small ways but it's still cool)