What’s this about putting a grinder in the freezer???

Long time joint smoker, but recently purchased a bong and a grinder.

I’ve seen a few people here mentioning putting the grinder in the freezer to get the Keef out, but like… how?

Do I scrape it out, does it end up in the Keef catcher part at the bottom of the grinder? I’m going in rather blind here so a quick explanation would be lovely!

Thank you in advance, fellow Ents!