I needed a way to ventilate a small, cheap greenhouse with a poly cover and one door. I outlined the small end of the vent on cardboard which I then used to cut a 1/4 inch SMALLER circle. (So the vent would fit snugly when attached.) I then traced it onto the greenhouse plastic cover. I punched a small hole in the middle of the tracing using scissors then cut from the the middle out into what would look like a ��plus�� sign, leaving the flaps attached. In between each previous cut, I made additional ones going toward the outside. (Like an asterisk.) So in the end, I had a 5 3/4 inch hole w a bunch of little flaps hanging off around it. The vent has 3 angled pieces of plastic on the part that would go on the inside. (Look at their provided pics closely) I am assuming is to help keep it attached to whatever it��s applied. I easily bent and broke them off. I then easily pushed the vent through and then from the inside, used GG Patch N Seal Waterproof Tape to hold the plastic flaps down and taped around the piece of the inside vent. If the flaps are a little too long, cut them down but leave enough to attach tape. I could��ve secured the vent from the the outside too w even more tape but chose not to so that it didn��t look too patchwork. This was so easy to install. I��m sure it would��ve been even nicer had I used something other tape to attach it but I didn��t have much choice. The inside screen should do a good job keeping bugs out too. I have absolutely no experience doing anything w tools, home repair, etc but installing this vent couldn��t have been easier. I��ve already ordered 3 more to add even more cross ventilation.(The clips were used simply to hold the greenhouse cover tight so I could apply the tape from the inside a bit more even. This was a job that had to be done completely alone.