How do you lay Ice and Water Shield straight?

I just started putting down ice and water shield on the roof. The video on YouTube made it look like a 5 minute endeavor. The first piece took me 1/2 an hour.

The problem is that the roll weighs around 50 pounds, and if you unroll the sheet to line it up before removing the backing paper, the entire roll wants to slide off the roof. The backing paper is like greased ice. I know the video shows sticking the first few feet, and then rolling it out / sticking it as you go, but I can’t figure out how to make sure that you’re lined up with the edge of the roof, and not heading off at an angle, either off the roof, or up to the ridge.

Can someone offer some good advice on how to lay this stuff out straight, without making a colossal mess?

Thanks.

I use a hammer tacker (stapler) and just tack it along the top black strip every 10-15 feet or so to hold it in place. Then flip up the lower (eve) edge and remove backing, let it stick to the roof. Then you can remove the upper backing strip.

Measure the length of the place your putting it and cut it that long on the ground. Don’t roll it over trash, rocks, etc. If it takes the entire roll to go across you can cut it in half on the ground. Either of these lessens the weight and will make it much easier to handle on the roof.

To keep it straight, you can pop a chalk line and follow that with the top part.

Im sure everyone has their own preference but I like to put the roll in place, roll out about 3-4 feet, peel the top half of the plastic up and back diagonally. Stick down a small area of that and then roll it out.