Assuming you're on PC: you don't need to put them in a folder, just click the file and it should open the plane in the game. You can also download directly through the Steam browser if you're using Steam, or by copying the URL and then pressing ctrl+L in the builder if you're on Windows.
How do you download simple planes on pc because i own the moible version
It should say loading whateverparcent%@sgttyler720
@Skua when i play the client it shows the plane i'm working on
Assuming you're on PC: you don't need to put them in a folder, just click the file and it should open the plane in the game. You can also download directly through the Steam browser if you're using Steam, or by copying the URL and then pressing ctrl+L in the builder if you're on Windows.
Theres a download button on planes ._. use it.