How can I prevent my prefabs from placing mostly in the ground?

Hi, I am new to Unity and attempting to make a Tower Defense game. Things have been going well up until creating Towers that a player can place. I made a prefab of a ballista inspired tower, but when I place the prefab during creation and in-game most of the tower is in the ground. I will include screenshot examples. One tower I manually moved up to show how I want it to place, the others are how it actually places.
I’ve tried adjusting the box colliders for the ground and the prefab but it still won’t align correctly.
Any help and suggestions would be much appreciated!

ted !

Design your prefabs with their local 0,0,0 at the level you want them placed relative to a ground at 0. If you are using models that someone else designed and they dip below 0, it’s probably so that it can fill in gaps when placed on sloped ground.

I did try that, the issue is that the prefab’s 0,0,0 is not the same as my ground’s 0,0,0. When I move them to the position I want them to be placed at and overwrite the prefab it doesn’t change the placement unfortunately. You mentioned local, are there different variants of the positioning, almost like layers? And this particular prefab was made from cylinders and cubes, not an import, so that shouldn’t be the cause.

Turns out it was the empty parent that was misaligned, after adjusting its position and updating the prefab it now places correctly