I watched the video again, and "think" I have it figured out now.

After opening the trap while compressing the spring with one hand, I have to grab the two "jaws" with my other hand,

Then hold it closed while setting the latch, then easing my hold on the jaws, to make sure the latch is "set"

Watching the video, I did get a bigger trap than a 110. My trap is about 6"X 6" and the 110 in the video looks to be about 4"X 4"

Virgil B.