There's more info in this article on Collider, but the pertinent facts are:
- The movie will take place entirely in the realm rather than having people transported from our world into the realm.
- The Yawning Portal will feature prominently and “it’s going to be one of people’s favorite set pieces.”
- It's an ensemble piece.
- Scriptwriter Leslie Johnson says "I believe they see Dungeons & Dragons as something that could be cultivated as a multi-universe movie where there will be spinoffs from the first movie being in Forgotten Realms and subsequent movies being in different worlds."
That last item is interesting. Different worlds? A Dragonlance or Ravenloft movie, perhaps?