How to make new parts from a part easily in Solidworks?

I have a .sldprt file. I want to split it into new part files. (see the image below) There is a car exterior. I want to make the doors and etc, another part files. And use them in assembly. ( ı want to open the door with my mouse :))
2 Answers

First, you need to make them separate bodies if they are not.
Use the Split feature, choose the sketch, click Cut Part and then choose the bodies you want to be saved, assign names so they will be saved as different parts.
Now use Insert> Feature> Create Assembly.
If they are already separate bodies, skip all that and use Insert> Feature> Save Bodies.