alignment problem

Swift 3d v5
I'm having a hard time trying to align, straighten the various objects. The big blue rectangle has to be flat on the ground. The gray panel on top and the red on top of that. The other blue objects have to be like a house. The ramp has to be from the gray to the ground.

I'm having a hard time putting this all together.

Whilst in the Scene Editor TAB, select your obejct and go to the Top Left Panel and select Position and Rotation to fix your the alignment issues. Trying to do this in the Viewport itself will be too hard.

you may also select more than one objects and align them to left or right or center from the align panel