The wrist strap has a thin loop on one end. Thread this thin section (like threading a needle) through the strap hole. (It's on the left side of the camera. There are two openings with a bar over the top of the center of them at the bottom corner of the camera body.) Start threading from the middle of the body of the camera and push the strap towards the bottom of the unit. You may need to twist the loop to narrow it and keep it tight. Once you have this narrow loop through the camera, open up the loop and slide the thick material through the center of this thin loop. Pull the wrist strap until the thin loop tightens around the bar.
This is shown on page 12 of the D30 manual. The manual is available from Canon support on the Powershot page: http://gdlp01.c-wss.com/gds/5/0300013985/02/psd30-cu2-en.pdf
. The direct link to the manual is http://gdlp01.c-wss.com/gds/5/0300013985/02/psd30-cu2-en.pdf
I hope this helps.
(Many lanyard straps for electronic gear work the same way. Threading the narrow section under that bar does require decent near point vision. People who are far-sighted may need to wear bifocals or ask someone younger to assist.)