Installing new light fixture with two sets of wires
The last guy left you exactly what you need.

Notice the orange wire and 2 whites hanging down extra low. Those are the 2 things you attach to. 

The lamp surely has a black hot wire.  Re-mark it with orange electrical tape.  Then off you go!  Done.  There is no ground wire. 



The upper tier of wires doesn't need to be capped off. They are already capped off.  Push them back into the top of the box and never touch them again.  It's your house and you can do as you please, but messing with those is the path of pain, unless you know more about electrical than I do. 

"I can see plainly that this wire is black and that wire is orange" does not qualify :) Wires in electrical are not color coded very well. Normally we don't even have this primordial color code, but since this particular installation is in the conduit wiring method, this applies: 


grounds: steel conduit or junction box, or wires bare, green, or yellow/green
Neutrals: white or gray
Hots: all others, colors selected to clarify/distinguish often by function, but there's no mandatory standard.  Must be consistent within the same building.  
...although, nobody with any style uses black for switched-hot.  Black is usually always-hot, and switched-hot is anything else.  One guess what your lamp does if you connect it to always-hot :) 


All grounds go together.  All neutrals do not. Neutrals that are separated, are separated for a reason.

You can wire a ground to the ground screw site inside that junction box if you really want to.  I wouldn't bother.  The ground screw site takes a #10-32 screw, and they sell a bag of ten adorable green ground screws for a dollar.