Rendering something on screen with CmdList and vertex buffers?

Hey guys, I recently found out about ImGui, which is a lightweight and great UI which is useful for debugging tools inside my game. The way it works is simple: it computes all it’s gui stuff, and outputs a CmdList and vertex buffers which are rendered on the screen. So before I can start with the ImGui implementation, I need to know how to render stuff like that on the screen using the RHI stuff. I found out that RHI also uses CommandLists to render, and with DrawPrimitiveUP it is possible to draw a cmdlist together with vertices on screen… Can anybody give me some starting help?

Thanks