What I have so far is when you start up the app it asks for a username and password if the info is correct it moves onto the full app. if it does not match it goes to the incorrect screen and has you try again. For testing purposes, it is set up as username = Test and Password = Test. for the admin all the login info is ADMIN but when the admin puts the correct info in it changes to the back door of the app where I want the admin to be able to create users (Usernames & Passwords) that will work in the sign-in page to unlock the full app. so far I do not have anything set up for the back door at all because I am stuck on how to code it. I don't even have any properties in. it's just a blank screen. If you could help me on trying to code this it would be great. ANY help is appreciated. Thanks. Reply if you have any questions or need any screenshots. 
Any help what so ever would really help
All users on the same device ?
Here are some resources to help you learn to use the AI2 tools. A very good way to learn App Inventor is to read the free Inventor's Manual here in the AI2 free online eBook http://www.appinventor.org/book2 ... the links are at the bottom of the Web page. The book 'teaches' users how to program with AI2 blocks.
There is a free programming course here http://www.appinventor.org/content/CourseInABox/Intro and the aia files for the projects in the book are here: http://www.appinventor.org/bookFiles
How to do a lot of basic things with App Inventor are described here: http://www.appinventor.org/content/howDoYou/eventHandling .
Also look here http://kio4.com/appinventor/index.htm and here http://www.imagnity.com/tutorial-index/ for more tutorials.
Learn about components http://ai2.appinventor.mit.edu/reference/components/
and visit the Library http://appinventor.mit.edu/explore/library Help>Library on the MENU
What I want is for the admin to go through the back door and create users (set up username and password) that will unlock the rest of the app. So I guess yea
You do not know ?
This is my first time creating an app and an just using the companion app as of now. Have not really thought about making it an actual app yet
Fair enough, but you do need to give this some thought, because it will be dependent on how you develop the app. In practical terms, it is unlikely that all your users will use the same device (?) therefore you will need a centralised online resource to handle the logins. See link from @SteveJG above. (CloudDB/Firebase/TinyDB/GoogleSheets/MySQL/Other)
Then decide if your need an admin app, when you can simply use the login "backend" to manage users
[edit] and why not let users create themselves?......
Ok, How would I convert a .zip file to a .aia file to upload to app inventor?
Nevermind. i just answered my own question. lol