Service/maintanace of Manitou fork and shock
There's three basic reasons to service your fork:
(1) it's not working correctly and something is broken
(2) it's working poorly and needs service to replace worn parts
(3) it's working fine and you want to keep it that way, i.e. recommended service interval

If it's #1 and maybe #2 you're kind of in a bind if you can't get replacement parts. The most common issue is worn or torn seals leading to leaks or air/dirt infiltration. You can't fix these and sizing is usually proprietary. If you're interested and confident you might as well take it apart to determine the issue. Just remember a poorly working fork is still better than one scattered in pieces around your shop!

If it's #3 you can likely do this service yourself without issues. The most common and frequent service is going to be replacing the oil and giving it a good clean. I'm not familiar with this particular fork but the damper assemblies are typically (a) complicated, (b) require semi-specialized tools (picks, lock-ring pliers, etc) and (c) don't need frequent service.

IMPORTANT! 
I Don't know if you have the air or coil sprung version, but if air you must remove all pressure prior to taking the fork apart! The Minute (air version) uses air in both the damping and spring - 2 separate schrader valves to relieve pressure.

As a general rule of thumb if you're having mechanical issues (play in the fork, "clunking", lack of travel/return) it's likely adjustment/tightening or something is broken/worn (bushings tend to wear and then do a poor job). If it's sticky, or sounds "wheezey" it's probably lubrication and seal related - this is within the realm of the do it yourself-er.

One final tip - often suspension uses crush washers and other "one time" sealing systems. If you don't have any spare parts be very careful when taking out bolts so you can hopefully match anything you'll need.