How Do Spider Webs Get Started?

When I walk through the woods in the morning, the trail is filled with spider webs, many, disturbingly, at face height. In some places the trail is four feet wide between closest branches on either side. So my question is, how did the spider get the first line across the trail, in order to build the web? I don't believe a spider can jump four feet through the air. Do they attach a line to a branch then walk into the tree trunk, down the tree, across the ground, up the other tree trunk, to the same height as they were? All the while they would be spooling out silk and not getting it tangled on anything? I don't think that's feasible. The weight of the silk line would be too much to haul up the second tree anyway. Maybe the spider throws or shoots the first line across the trail. But I don't think spiders can do that. Another possibility is that the spider fastens a line high up on one branch and then swings like Tarzan across the trail to a branch on the other side. That seems improbable, but it could be right. I wonder if they beat their little spider chest with eight tiny fists as they swing from the silk line, and even let out a spider-sized "aah-eee-aaah!" as they make the trip.