How do you make the model 3D printable? Are there any steps to follow?
Yes there are specific standards to follow for 3D prining. We have a 3D-printing course but it doesn't include model-prep in this sense (modifying a non-printable model into a printable version). I recommend this video from Grant Abbit:
Ah, this helps thanks. I've only just started with 3D printing and 3D modelling. So there's so much to learn
Is his method of preparation overly difficult or complicated at 6 minutes 45 sec into the video? He’s sculpting a shape to fit inside his mesh. Does that not become extremely difficult near the facial features?
That's note exactly how I would go about it. But the concept he's presenting of hollowing out the sculpture to save resin is a good one.
Personally I would opt to duplicate the sculpture, decimate it down to a lower poly basic version, tab to edit mode and ALT + S inward to create a shrunken volume representation that would then be booleaned away. Same concept, different execution.