I'm gonna keep this short and sweet - if your razor isn't assembled correctly, it won't shave! I mean, maybe a little, but nothing like how it's meant to.
The "middle plate" must have the comb facing upwards against the blade, and the smooth side should be against the handle.
This is often the no.1 reason why people think their safety razor doesn't work for them.
Then you want a 30-degree angle (same as a regular razor) and short strokes.