Door & bow extension question

[Guest guest]

My bow extension pack comes with 3 strap extension lengths complete with fixed

handles plus door jam loop. The color chart shows the extension straps being

used without the handles when used on a door jam. My straps must be a newer

version as handles seem to be now permanently fixed to each strap, same as the

iso-bow.

The question: How do I rig up a strap to the loop extenion to do the iso-motion

" door jam " exercises?