There are many apps available that are used to view files, or install files, or manage files.
The Buzz box has a few onboard , or pre-installed.

I do mention a few times in the text below ... "installed apk file" ... but in fact it is the application (app) that is installed and the apk file is basically just a carrier of the app.
So please forgive me for my slightly incorrect terminology

Open the APPS menu icon from the main Buzz screen

-AppInstaller
This is where we can install apk files onto the Buzz box.
Apk files a way to install an application thru USB device drive. Once installed, the APP can be found in your My APPS menu.
You will need the apk file placed on a FAT32 formatted USB drive.
Always try to have the USB drive inserted into the Buzz box while the Buzz is powered off.
If the drive is not recognized, then use the Power icon on bottom right on main Buzz screen and Reboot.
Then enter AppInstaller again and the USB drive should now be seen.
Appinstaller does only one thing and that is installing an Application (app) from an apk file.

-File Browser
Another apk installer.
If the USB is not seen then again follow above procedure.
On File Browser's main screen you should see..
-Local Disk
-USB drive
Open USB and you will see the contents of the drive.
.txt or any files can be opened and seen onscreen.
.apk files can be installed, just click to install.

-File Manager
A mouse is needed to use some functions nicely with this File Manager.
There are alot of functions in this APP, hence the Manager title.
Local Device & USB Device are seen here and can be opened.
Content of USB drive can be opened or installed.

Here we can also see a list of categories (just below where you see the USB Device, use mouse to scroll the page down).

-Large Files
-Unnecessary Files .. here we can clean up temp files or log files and empty folders.
-Used APK Files .. here we can remove used apk files.
-Installed Apps .. here we can uninstalled previously installed apps.
-All Files .. here we can see storage use by analysis percentages.

There are details and functions to be used in each category (such as deleting used apk files).
Not necessary but an apk file can be deleted after the application has been installed from it (this saves a small amount of storage space on your Buzz).
Just do not delete the root path of it.
APKs in /system/app/ need to stay where they are to function appropriately.
To see apks on system, follow path mnt/asec
Many other functions here can be found on the side bar menus, have a look around in them.

In the market (AptoideTv) you can find other similar apps, such as ES File Explorer.
That ES app has always been a good app as well.