Pull the old scrapers straight up -- some force may be required to get old, stiff ones to pop out. Put a little bit of dish soap on the rubber bead at the bottom of the new ones to help them slip in, and push them in an inch or two at a time.

The trunk seal glues in. Find a store that specializes in automotive paint, and they should have a glue that's strong enough (sorta like industrial-strength contact cement -- ask for advice). The ends of the seal meet at center bottom, not top. Use masking tape to hold the corners in place while the glue dries, and anywhere else that wants to come adrift.