What does the building airdrop in Red Alert 2 mean and how to operate it?

This is easier to pull!

First, the building you want to build is ready.

Move the screen to the place you want to build.

Left-click (mouse) on the building you want to build. That box,

Click the building mode button above, don’t release it,

keep dragging it out, and drag it to the ground,

Right-click, double Press the keys at the same time,

That tall building! The ground is flat!

If this building is a barracks,

if it is built directly on the enemy side, you can directly create spies!