Adding New Overhead Light

Any help with the following would be appreciated:

Just bought a house built in the mid 1980s. One rooms does not have overhead lighting, which I would like to add.

The previous owner added the room on. I went into the attic there is pleanty of room to work.

I bought the overhead fixtures I wanted (2 8' sections of track light with LED lamps). Cut a hole in the ceiling and

attached a ceiling box for each track. Connected track light wiring to boxes as per instructions. Bought 12/2 cable.

Ran a length of this new cable from each new ceiling box to the wall where I want the switches, left several extra feet.

The breaker box is on the outside wall of this room and has several 12/2 wires running through a large hole in the attic.

The previous electrician left a wire loose labeled "FUTURE" (I intend to use it for the lights).

I have the switches, the wall box, and a metal box to go in the attic. I want to separately switch each track of lights.

I now have mounted the attic box and have all the wires run to it. I have also mounted the wall box and fished 2 lengths of cable to the box. How do I proceed from here?

Thanks