Ground wiring and the positive wiring?

Hello, what color is the wire you're dealing with? And is it a solid color, or one with a stripe on it as well? The Starter looks to have just a purple wire and a red wire, the red wire branches off to the Charging System.
It looks like there is a Black wire with a White stripe that is a Ground going from the under-hood fuse block to the transmission case. I'll post a diagram of that.
The 1st diagram is the upper section of the Starting System, and the 2nd is the lower half.

Okay, I'm going to post the OEM manufacturer diagrams as well because those aftermarket ones look different in some places.
This is the OEM starter diagram.

Okay, let me go through these diagrams, that 1st picture with the 3 or 4 black with a white stripe are Grounds, are all these wires that are disconnected near the transmission area? It looks like the Grounds for this vehicle are all either black, or black with a white stripe. This is G103 and G105 which are both in the engine compartment. That 2nd picture I can't tell what color that wire is, but it looks thick like a high amperage wire.
Do you have the 2 wires on the Starter motor yet?
Except this power wire from the Starter to the Alternator is Black with a fusible link. I don't know why they do that; this will be a high amperage wire. Be careful with that one. It will run to the Alternator or From the Starter if it's not hooked up yet.

This 3rd diagram is some OEM power diagrams with red/black and red/white wires.

The black and red, or red and black is a positive wire? There are a few Red/Black wires, there are 2 of them that go to the EBCM (electronic brake module), Power steering control module 60amp, BCM 40amp, those are in the engine compartment. And that wire at the top of the diagram labelled A, goes to a relay on the 3rd page of the diagram that powers the windows, door locks, radio, so basically accessories.

So, that one you're holding in the picture is already bolted to the fuse panel, and you can't figure out where the other end goes? Does it reach to the Electronic Power steering? Thats a 60-amp circuit for the module, The EPS is a red/black wire.

So, it was the Charging wire to the Starter? I know there were two red wires going to the Starter, but it's easy to get confused when they have so many main power feeds the same color, I have learned to also take a picture before taking things apart in certain situations. It can save a lot of time and headache in the end. Glad you figured it out though.