Help needed on Freecad

Hello everyone,
Quite new on CAD here, trying to design some simple parts to get some practice.
One question I couldn´t find an answer to anywhere online: When working on FreeCad, can I make a pocket at an angle on a body? Just to be clearer, I want to insert a hollow slot at 45º into a cube. I am working on Freecad v0.19, btw.

Many thanks!

Sure you can. The preferred way is to use a datum plane and “mount” it at the desired angle. Now place the sketch onto the datum plane and create your sketch and pocket.

You could also angle the sketch directly by changing the mount point angle, but I would go the extra mile to create an independently surface to work on. This make later changes so much easier.