Different Spiders have different methods. Most fasten one side, walk or jump to the next side, fasten here and build from that string.
If they can't get to the location they may drop down the silk or it-self and let gravity or the wind pull more string until it hit something and sticks to it.
10thousand years
Camel spider A dead one
Spiders that spin webs do so as a means of catching food. Another reason for webs is that male spiders use them during the process of reproduction.
spin
Ask a spider
The lynx spider does spin webs but only for one reason, to hold the eggs. otherwise this spider does not use a large web for catching its prey.
Spiders of both sexes spin webs.
spin a orb
It comes from an Old English word meaning "to spin". (http://www.merriam-webster.com/dictionary/spider)
"its" is a possessive pronoun. "spin" should be "spins".
They are born knowing how to spin a web.
Depending on the spider, it has been estimated at about 200 yards a day