Best to find out exactly what FAN it is because there are certain fans that have built in cover mounts like the MAXAIR II that makes it easy to install the fan covers with just cotter pins. Others you have to drill holes in the side to mount the cover hardware or unscrew a couple of the roof screws in the fan to install the mounts.
All of them are fairly simple installs, I have done all three between our previous 5th wheel and the now Motorhome that has the MAXAIR II vents. Just installed the Smoke MAXAIR II vent covers on both our fans - all of two minutes to install due to the fans having the cover mounts built in.
https://www.etrailer.com/RV-Vents-an...IR/MA26JR.html
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S&T
2019 Entegra Insignia 37MB
2022 JEEP Wrangler 4xe (chase and touring vehicle)
(2019 NP 383FKWS)
(2019 RAM 3500 DRW Big Horn)