"if you regard being 'professional'"
Professional doesn't necessarily have anything to do with the amount of $$ you make... it's an attitude... part of such is doing the best you can while looking your best.....

"but I've never done it before"
I'm not suggesting you install the endpin jack yourself.... take it to a trained technician....

"things that look easy often aren't"
That's just a matter of experience
:-)