Confusion about sharing after changes

I'm getting confused about how best to share my application with my colleagues.

I'm building an internal system that a great deal of my co-workers (50+) will be accessing. We're currently in the testing phase, so i'm still adding new views and forms to the app. I find that even though I add these users in the "sharing" tab, the new views/forms don't automatically show up in their view of the app, but instead a second listing of the same application shows up in their Shared Applications tab and they have to select the most recent one.

If I'm understanding the above correctly, moving forward, this is going to be a big problem for us as I'll need to make improvements to the system while it's a live application, and I won't be able to tell upwards of 50 people to go and click on a different link every time I make a change. Is there any way around this, and am I missing something here?

I'm also confused about how the user license numbers work and how to sign up new users -- when I add a user in my control panel, does that create an account for the user?

Thank you!