Others should feel free to chip in their own answers/clarifications (especially for Mac or Linux instructions):
Install Git (http://git-scm.com/downloads) & sign up for GitHub (https://github.com/).
Download & install Android Studio: http://developer.android.com/sdk/index.html
Then follow the instructions on the web page it redirects you to, to update the SDK tools, select all the recommended extras (like Google Play Services), etc.
UPDATE: You'll need to install the "Google USB Driver" under "extras" in the Android SDK manager.
To get the loaner Nextbook tablets to be recognized by your computer: (Similar steps likely necessary for your personal Android devices).
- Plug in the device
- Update the driver with the one from Google. Go to "device manager"->update drive->let me pick from list->"Have Disk"->"Browse" to "wherever-you-installed-the-android-toolkit/extras/google/usb_driver"
- Find or create the file in $HOME/.android/adb_usb.ini
- (Note, for most Windows users, $HOME will be "C:/Users/YourName/")
- You must add a line of text "0x2922" (which is apparently the Nextbook vendor id) to that file.
- When you connect the device, an "authorize" window should pop up on the tablet, which you must accept.
- On your own devices, you need to enable "USB Debugging". Instructions here: http://www.kingoapp.com/root-tutorials/how-to-enable-usb-debugging-mode-on-android.htm (Note: although that site talks about "rooting", note that you DO NOT need to root your device in order to use it for Android development.)