Load AssetBundles and External Scenes dynamically

As the title suggests, I'm in need of help on how to load AssetBundles and if possible, external Scenes (as bundles?).

My hope is to have multiple scenes (and their respective GUI scripts) to be saved out to other developers and exported to a bundle for inclusion into the "master file".

Here's my breakdown:

• Main Menu (Main file.exe)
• User Profile
• Settings Screen
• Game
• AAR

I want each scene to be a separate development file where when ready, can be exported / ready for loading into the larger main file. In addition to my separate scenes, I also want a few other assetBundles of just Models that I can pull into the main file on an as needed basis.

How can I achieve this? I know what I want in theory, but when it comes to the actual execution, I'm at a loss.

I've spent a few hours on the web (and here) looking for an answer, but to no avail. Any help would be greatly appreciated!