So I've got a sierra 1500 5.3 liter v8. I had to replace all of the break lines and this is technically my first time under the hood of a vehicle .... I know I know . It'* ok I learn quick.. Anyways the issue is i had to remove all of the lines at the same time to get other lines out. And now I'm uncertain on which port on the abs runs to the front or back of the master cylinder. I purchased pre fitted lines and i have already fitted them up and through but I don't want to start running the front lines through until I know for sure. Does anyone have exact information of the abs diagram on this year and model I've searched everywhere and found some But like I said I'm serious this is my first time working on any vehicle.

First timer on a vehicle playing with brake lines?? tsk tsk. Mark, label, tag everything you remove.
Your best bet would be to go to a junk yard and find similar chassis to yours. GMC Sierra'* share a lot of commonalities with Chevrolet 1500'*, Express etc. Take pictures. Done.
BTW, this was posted in the wrong section-this is the Pontiac Bonneville 1992-1999 section. Moving this to Chevrolet truck/SUV.

Ok So I just went to the Dealership and had a 99 Sierra I am changing the engine on that I had pushed outside till the motor got here. It is 45 degrees and raining so you better give me a Thanks on this post and donate to a charity in my name! Ha. Also I created a 7 year old child'* picture for you lol.