New Rider with Old Bike in KCMO ('81 550 LTD)

Hello everyone! 
Excited to be apart of this community! 
I am a new rider, got my license back in April, who got an '81 KZ550 LTD as a first bike! I was lucky enough to have it gifted to me by my cousin's husband. It has been sitting for four years and doesn't run lol. My buddy has a '79 KZ650, so I have it at his house so we can work on it together. Currently, it is getting no power throughout. I have a new battery but nothing is happening. So, I think it's the ignition switch (we followed the hot wire up to it and no power is coming on the return) and or the rectifier. I will have a lot of questions since I have never worked on a motorcycle before. I have experience fixing homes, so not new to tools or problem solving, but mechanically speaking, I know absolutely nothing. lol But I am excited to learn! Hope to learn a lot from this forum and look forward to fixing up the bike to hopefully go riding before the season is over. Thanks for reading if you made it this far lol

 

Welcome from the UK, you will get all the help and advice you need here 

Welcome aboard. You will find the factory service manual indispensable in getting your bike back on the road. Here is a digital copy.   www.kzrider.com/modules/ServiceManuals/Kz400500550_79to83.pdf

There is also a great deal of very important and useful information, much of which is not on the manual, at the following website. I strongly suggest copying as much of it as you can, as it will one day disappear without warning. The author of the site was a manner here who died recently, so the web hosting service will likely take the site down one day. I believe another member here has downloaded the site and may be able to send you a copy.
s3.amazonaws.com/gpzweb/CamsKZZXZR550500...KZZXZR550500400.html

Here is the home page of Lou’s rather extensive website -  s3.amazonaws.com/gpzweb/index.html

Welcome! Nice bike My son and I are are working on getting his 1983 KZ550 shaft up and running again after 3 years of neglect. He loves that bike.
Question for you. Does that tank have a one bolt mounting or a two bolt mounting? If it is the two bolt; take care of it. They seem to be as rare as hen's teeth. I get to learn dent removal this weekend due to a drop he had years ago.

Thank you so much! I really appreciate the manual and the link. I will make use of them for sure!