There are two ways to bind carpet. One way is to lay the binding back away from the edge, sew it down to the carpet anywhere from 1/4 to 1/2"from the edge, fold it over the outside edge and glue it under the back side of the carpet, and then "sew in the ditch". This means sewing right next to the binding towards the inside on the top side of the carpet. This works fine until you need to turn a 90 degree corner, and then it becomes almost impossible for a beginner.
The other way is to fold the binding over the top and bottom of the carpet simultaneously and sew both sides down at the same time. This way is much easier to turn 90 degree corners, but shows the stitching on the top side of the binding. Personally, I like to see the stitching, but that's just a personal preference.
On thicker carpet, sewing in the ditch works much better. On thinner carpet, sewing through both sides at the same time is much easier, but either way will work fine.
No one lives forever, the trick is creating something that will.