wiring questions???? please help!!!!

[rodstored-72]

hey guys,
well i am trying my best to fire up my engine in the truck ('72 chevy 2wd shortbed) for the first time. i have a new batt., all new wiring harnesses (engine & lights). i talked to the place that i got the harnesses from & when i explained that i had HEI distributor then i was told that i needed to splice in a red 12v wire to handle a constant 12v pwr supply. he told me to take out the two yellow wires from the engine harness (1-starter & 1-to coil). he said that the yellow wires were not needed, just the prpl wire to the starter. he said to cut the wht. wire (which was the main wire for the 2 yellow wires)all the way back to where it turns to a maroon color (right at the balkhead) and then splice in a red wire to run to the hei distributor. i have done all of this & have re-wrapped the complete harness. i now have the wires hooked back up to their respective places. i am not sure what to do now??? . i guess i am wondering how the power gets from the starter to everything else?? the pos. batt. cable goes to the starter, & the neg. batt. cable i have hooked up to the front of the cylinder head (next to the ac. comp. bracket) so i figured at the very least i should have pwr to simple things like the lights & etc. - right?? i also have the 2 grounding strapes hooked from the firewall to the back of the cyl, heads. anyways i guess i am looking for direction on what i have done so far & direction on what i need to do to get this motor that i have spent a pretty penny on to fire up!!! . if i could get some major help from you guys here i would really appreciate it!!! this is my first rebuild & i like to do this stuff, but it seems like the tasks are at times more then i bargained they would be thanks again for any input that you guys are able & willing to share!

very confused,
rodstored-72