THIS IS A MINI CAUKLING GUN, not a full size caulking gun
Specific Product Link: https://www.bunnings.com.au/monarch-mini-skeleton-caulking-gun_p1662107
Basic how to caulk: https://www.homedepot.com/c/ah/how-to-caulk/9ba683603be9fa5395fab9012f8277f
Detailed guide to caulking: https://todayshomeowner.com/homeowners-guide-to-caulk/
Basic how-to video: https://youtu.be/5k9FaelUzyo