To be able to make your own obstacles, you’ll need some knot knowledge. Here’s four basic knots with which you can do a lot:
Clove hitch
With this knot you can fasten a rope around a pole, e.g. to make a swingover.
Reef knot
With this knot you can tie two ropes of similar diameter together.
Bowline
With this knot you can make a loop that does not move, e.g. to put a tyre on a rope.
Prusik
This knot is easy to shift if there’s no tension on the rope. The more loops, the more fun.. they also prevent unintentional shifting.