How do I resize a tree prefab

Yes, I have googled this and have not found exactly what I was looking for (most have to do with older unity versions and are applicable while the others were of no help).

So I bought trees on the asset store. If I import them into the terrain tree builder, it will not resize them. I can change the scale on the prefabs to 20-20-20 and individually place them on the landscape. However, in the terrain tree area, it will not use the scale. It seems like it only will accept the slider for width and height,

So Is there a way to change it so I can make them 20-20-20 on the scale as the terrain tree area’s max setting is to small.

You can most likely use the scale factor on the tree model. Click on the Tree model (not the prefab) in your project view. The scale factor is now at the top of the inspector in the import settings for that model. Increase it and see if it works for you. Keep in mind that this will increase the size of all the trees of that model already placed in a scene. I also recommend you to double check that you actually need the trees enlarged, as the trees on the asset store should be scaled properly. Put something you know has the correct size beside a tree you have placed on the Terrain.