those are not complex shutters, if you google around you will find many resources -- generally speaking you unscrew the lens, there's usually a retaining screw or ring holding the face plate on, which you take off, Under that is another ring with cams cut into it that you can see levers on the mechanism engaging in. Take that off, you can see the slow=speed train. Most people use a good solvent and very very very little oil.

this web site goes into many shutters:

but if you are at all unsure, or tend to lose little bitty parts, and you want to use this to take pictures and be reliable, send it off. Essex Camera Repair charges $90 to do one of those, and worth every penny.

Look at it this way -- sure, that's what another shutter costs, but ALL those shutters are 50 years old and need a go-through.