Way to edit static mesh from Autovrtlenv


For a project I am working with the automated driving toolbox from Matlab and the option to create a custom scene with Unreal editor.
I am able to create the scene that I want however the vehicle that will be driving around in this scene will be different from the provided cars that I can use now.

I want to make it very simple and have the vehicle be represented as a white block of certain dimensions.

I tried to edit the mesh (which is a .uasset type file) of the cars however this doesn’t seem to work as I think I need the source file for this. I was able to change the file and load the edited file into the scene, but then I was unable to use the edited vehicle to drive with. So I think that the file that is used for the actual driving as saved somewhere else that I have not been able to find yet.

I also tried to maybe add a socket to the mesh and attach a white box that will then cover the vehicle however I am not able to attach this block to the socket in the scene editor.

Can anybody maybe help me with this?