Apparently he plays with two forwards.
I see this
Rashford/R7 - Greenwood/Amad
<-Sancho->
Bruno - VDB
CDM
I don't think he's wedded to it and he's used 3 across the front and 5 at the back too. I won't be surprised if it's Bruno as Forsberg tucking in and then 3 across the front with VDB in a similar role to the one Sabitzer or Kampl have played as the highest pressing in a double pivot.
He's not current Conte where you know for sure what formation you're getting. All we really know is that we'll probably try to force the ball wide as a trigger to the press and on the ball he wants tempo and hitting it forwards rather than a slower side to side possession game.
I'd guess Cristiano (Cavani backing him up) will be a similar figure to Yussuf Poulsen/Andre Silva as neither of those are particularly fast and trying to play vertically in possession means you need a strong #9.
Bruno maybe similar to Forsberg, playing as a #10 in the half space mostly, though that could also be Sancho's role with Bruno figuring deeper. Rashford is the most similar player we have to Werner if he's looking for pure pace on the break.
So yeah, it might be a 4-4-2/4-2-2-2/4-4-1-1 like Hassenhutl (whom he presumably picked) plays at Southampton and Rangnick mostly used at Leipzig. If so, they lineup with a proper 9 in Che Adams, presumably that's Cristiano, and a 2nd striker behind him (they spent big on Adam Armstrong to fill that role with Ings going) which I imagine would be Rashford or Greenwood. Sancho and Bruno behind them with Sancho wider (like when Southampton play Djenepo, Redmond or Elyounoussi and Bruno more tucked in like Forsberg at Leipzig or Stuart Armstrong at Southampton, and then 2 in midfield and I imagine Fred will be one, and then everyone has decided Van De Beek the other one, but he's still a new coach. He might fall in love with Pogba's ability to pass the ball forwards and break the lines which he does with France consistently better than basically anyone else in the world game along with Verrati. We really have no idea.
So yeah, forcing the ball wide, trapping presses once it goes out there, Cristiano up top and he said he didn't rate Shaw so maybe Telles at left back, but other than I'm not really assuming much.
In terms of educated guesses, I could see a honeymoon period for Lingard until he sees that he's among the worst vertical passers you'll ever see playing as a #10, and Fred seems tactically smart and mobile enough to be in his first choice midfield and Van De Beek will probably understand what he's trying to do better than most. I think the appointment could be very good for Rashford, since Rangnick/RB seem intent on having speedy players stretch the play the second the ball is turned over and Rashford makes the best vertical off the ball runs on the team (now that Cristiano is old of course).