Hi,
It's nine years since I owned an MZ 2 stroke, but from memory: the two buttons are - outer, horn; inner headlight flasher. You can get a simplified wiring diagram here:
http://f1.grp.yahoofs.com/v1/AENjSrof-okS1lLRvtwgpiORl8lJ358B_DndJVee3R3spidVWob4r-_Zw0BzUYjePrtWqz7tev7AHX1oYXxcqH9_ilnX6w/Simplified%20Circuits/ETZ251%2C%20Later%20ETZ%20125-150%2C%20with%20Rev%20Counter.pdfIn case this doesn't work (you might have to register), go to
http://groups.yahoo.com/group/mz_riders/ click on 'Files' at the left hand side, then click on 'Simplified circuits', then pick 'ETZ 251,....'.
It's worth joining this e-group as they are very knowledgeable and helpful when it comes to the 2 stroke models.
As for your indicators; first check the indicator fuse, then the flasher unit. The old DDR built ones were very unreliable and can be replaced with any suitable car unit.
Can't remember the order of the main (ignition/lights switch), but no doubt some who does will be along in a minute. If not, ask at the Yahoo group.
Good luck,
Norman
http://www.mzskorpion.net