A sheet bend is used to attach two ropes together.

How it’s done:

For this knot I’m going to use two ropes. One of them is white and the other one is yellow.
First make a loop with the white rope.

Then put the working end of the yellow rope on top of the loop.

Now behind.

Turn up.

Turn around the white rope but pass in front of the yellow one. It’s important that both working ends stay on the same side.

It’s done! 😀