Step 1: Supplies
1 inch tubular webbing- (at least) 70 feet
carabiners - 5
carpet (1ft. by 3-5ft.)
2 trees, poles, or any two VERY sturdy upright objects
Step 2: Anchors
so, once you have the webbing, you need to cut of TWO ten foot sections (make sure to burn the ends, so the webbing won't fray). these will be the anchors.
Now, tie a water knot on both ends of the ten foot sections to make a big loop.
you can see how to tie a figure water Here
Step 3: Knots
Step 4: Set It Up - Anchors
then wrap one of your ten foot sections around the carpet and put one carabiner on the ends of the loop
do the same to the other side, but with two two carabiners on this side. make sure that BOTH carabiners go into both loops with the gates facing out
Step 5: Set It Up - Slack Line
now walk towards your other anchor holding the line to make sure that there are no twists. when you are about 4/5 of the way there tie a clove hitch, put 2 carabiners through the two loops you make in the clove hitch.
Step 6: Set It Up - Slackline
now PULL, this might take more than one person. you want it to be pretty pull until it won't go anymore.
Keeping tension on the line, tie at least three half hitches around the webbing that is in between the sets of carabiners. I recommend tyeing them on a bite, this will make taking down the line much easier.
Step 7: Set It Up - Slackline
Step 8: SLACKLINE!!
Note that it will take a while for your line to stretch out, if you notice the line getting loser, it is probably the webbing stretching.