Sure it lcan be learned, just like any other trade.
Vocational schools used to teach camera repair. I'm a graduate of the course at National Camera.
You can get tools and supplies from Micro-Tools in Vacaville, California. It's the largest supplier of such to the repair industry.
One key to doing a complete camera repair, resulting in a camera that will work properly for years to come, is lubricants.
Some of them can be expensive, like Nye Astro Oil (no longer available) at $90 per ounce.
The proper adhesive for replacing leatherette is Plio-Bond.
One thing that can get you into trouble quicker than anything else is screws. Make sure you return each one to its original place... no exceptions. The small screws used in manual cameras can differ in length by a small fraction of a millimeter, but that can be enough to cause the camera to not work if you put one in the wrong place.