Nice when you get them out and they start ok, certainly good weather for it today.
The side panel lugs, I use silicone grease from plumbing supplies on them. It doesn't dry out and they usually just easily pass through the grommet.
To glue them, you can try some of the solvent type plumbers also sell for "polypipe" installation. If you rub a small amount on a discreet part of the rear surface of side panel, it'll show if it'll bond that material.