If there's a lot of lint still in the vent, vacuum it again. Tidy up the floor below your dryer vent, collecting any lint ...

Insert the vent and screw the cap to the house (predrill screw holes). Push foam backer rod into deep gaps. Caulk all around with acrylic caulk. There are two good ways to install dryer vents ...

If your dryer vent is anything like mine, expect a lot of lint to come flooding out of the wall. The amount of junk that littered the laundry room floor brought my upright vacuum to its knees.