Side loading is the process of moving files from one computer to another via USB, MicroSD Memory Card, or by using online storage.
The simplest way to sideload apps on the Kobo Vox is to use your computer to send an e-mail to your e-mail account, and attach files to it like APK Android Installer files, MP3s, and other files.
Next you use your Kobo Vox's browser which has Wireless Wi-Fi internet to download your Apps and files to your Kobo Vox download section. After you downloaded all your files from the internet, you can install your Apps by opening the .APK file which is the Android installers apps for installing files.
Once you installed the App, and it works, you can delete the .apk file if you want.
You can also use a MicroSD memory card, or side load apps by connecting your Vox to your Computer with the .APK files, but you need to use a file manager like File Expert to find and open your files and find them. The MicroSD folder is MNT/EXTSD and the internal SD Card is found at MNT/SDCard folder.
If you want to organized your downloaded apps you need to use a file manager program like File Expert for Android which can be used to move, copy, and paste your files to different folders. You can also use File Expert to search, and make new folders on a MicroSD memory card or your internal memory card on your Vox eReader Tablet. File Expert also has Wi-Fi, and FTP features, so you probably can use the Wi-Fi file sharing, and FTP features to use the internet or wireless wifi connection to side load apps on other Tablets.
Generally, you can just use your Gallery and Music App which comes pre-installed on your Kobo Vox to open compatible multimedia files like MP4 video, Jpeg photos, and MP3 music files, so you don't need to organize your files to find them since you can just use the Gallery and Music App to open them, and these Apps automatically display new media files in its playlist.
You can use the USB cord for your Vox to move files to your Vox's memory and microSD Memory card's data, but you need to turn your Vox ON, and turn on USB Storage mode for your Kobo Vox.
You need to use the USB cord which cam with your Vox since the Vox uses a weird plug which only works with its own USB cables, and not Micro-SD.
Using a USB microSD memory card reader is a lot easier and convenient then using a USB cable since you don't need a USB cable to connect your ON Vox to your PC. All you do is plug in your USB card reader with your MicroSD card inserted in it on to copy files like a regular hard drive, and eject your card reader from your computer, and take out the MicroSD card from your card reader, and gently push it into your MicroSD card reader on your Vox till you hear a click.
You usually don't need to format your MicroSD memory card since most cards are formatted to FAT 32 or FAT 16 which Google Android can read and write to.