How do I make it so I can move my mouse when I'm not in the gun?

Hey,

I'm making a TPS Game an I Imported one of Roblox's Gun Models:

https://www.roblox.com/library/4842218829/Sniper-Rifle?Category=Models&SortType=Relevance&SortAggregation=AllTime&SearchKeyword=Sniper&CreatorId=1&Page=1&Position=1&SearchId=09a251bd-084b-44af-aa2d-a73d5b030c26

I was wondering how do I make it so I can move my mouse when I'm not equipped the gun but so I can't move my mouse when I am equipped the gun

Thanks :)