There are two ways to take off.
1) the yellow 'launch' button on the screen.
2) pull both control sticks down and inwards at the same time. This spins up the motors. With the motors running at idle speed: you then push the throttle stick gently...
I always head straight here:
https://www.caa.co.uk/drones/getting-started-with-drones-and-model-aircraft/drone-code/updates/#
Any major, minor or planned changes clearly stated.
I think the real point is that this isn't something that is made plain to prospective purchasers... I was one of those people that threw a blue-arsed fit when DJI released that firmware for the mini 3 pro that hobbled the max altitude to 400'...
...and because it's now in a heavier weight class: as pointed out by Gadgetguy, you don't have the freedom to fly in any of the places a sub-250grm drone can under the A1 sub-category, you also are now limited to flying in accordance with A3...