Alternator/charging system questions for model 917 254410

Hello Guys, I have several questions regarding the alternator/ charging system on an old GT 18 I drug home the other day. 917 254410 To begin with the wiring was a total NIGHTMARE. The ignition switch was replaced with a single toggle switch. (with the switch in the down position it was off, center position it was on, and pushing up on the switch would engage the starter) There were wires going nowhere, wires cut, spliced, etc,etc. I was told that the tractor had been sitting for several years. It has an 18 H.P. Briggs horizonal shaft engine. I cleaned it up and got it running (Runs fine) and thought I would sort out the wiring. What a mess. I decided to eleminate the wiring and start from square one. I wired a "Kill " switch directly off the mag for the on/off. Then I wired a push button switch to activate the solenoid and that works fine. My first question is how can I do a test on the alternator? The tractor has 2 black wires coming from the alt. and into a small plastic box which is the regulator? And out of the regulator is one red wire with a white stripe. What do I need to do to check the alternator? And my second question is if the alt. checks out OK what wiring do I need to do to so that it will charge the battery? I have found the wiring schematic but being as Electrically challenged as I am I cant figure out how to wire it so It will keep the batt. charged, and run the headlights. I was hoping that You Guys could help me figure this out. Thanks in advance, Litz