Don,
First of all Congratulations on your purchase of the Chord Mojo For the money you will not find a better DAC/HP-amp I have even experimented with this DAc with my High End main system . You can download the Manual from the Chord Website but let me see if I can help.
On the left ( 3 marble buttons facing you) you have 4 inputs 1. COAX, 2. mini usb input 3. Battery input ( is only for charging will not play any music )4. Optical input . on the right side you have" two inputs for Headphones" or with a proper harness can be used as a DAC for a larger system
The Battery should last you for about 8 hours you can play while charging but it gets very hot ! There is no app for this unit ( for windows OS yes) but not for Mac OS it is a straightforward unit you need to connect it to you computer or your laptop with one of the inputs on the left side coax, , optical, or mini usb cable for instance I use a glass Liftac optical cable to connect to my desktop mac mini if I want to use it with my Iphone I use the mini connector cable plus a separate camera adapter cable from Apple website ($29.00) you can also buy the whole adapter kit to use with various devices from moon -Audio PM me if you need further instructions I will try to send you some pictures ! This unit will play Hi-Rez right up 765Khz

Asghar