I want to put a cube in to the another cube floor

is it possible? if possible how can i do. i dont determine the cube position.

How do you mean exactly? Do you want to randomly add a cube static mesh on top of another one inside a BP?

namely, i want to enter a lenght in to the program and create a cube from this information. and i have another small cube information. i put the inside big cube specific position that i know. How do i do that? i know where i put it but code dont know.