How to Split 1 body into 2?

Hello,

I am working on a project that requires a undermount drawer slide from blum. I manage to get the step file from the website but, the model only comes with a single body. As is it suppose to work as a slider, I'm thinking if there is anyway to split the drawer slider from the cabinet mount so that I can use joint to animate the drawer. 

https://a360.co/38TxpX4

Is Fusion 360 for me? why?

Hi everyone, I have project in mind which is a desk with drawers mounted on a pair of square tubing welded legs. 1 of the drawer will have a PC built into it. I've actually already built a working prototype. However, I realize that without having done proper modeling of the project beforehand, I ended up with a lot of issues when constructing the desk (I have attached a image for reference). Therefore, I would like to learn some 3D modeling so that my next project will be better executed. 

I've heard of other software such as Autodesk Inventor, SolidWorks, Blender etc.. So I would like to know which software is a best fit for my use case? Also, can Fusion 360 model computer parts?