Depending on when you read this, Steam Family sharing is either in beta or finally released to the public. Either way, if you're going to share your Steam library with family members after years of building your library, you might want to limit which games they can actually see!
It's been possible to share your Steam library with family members for many years, but the way it worked is that you shared your entire library and if you started up any game on your PC, the other user would be kicked out—even if they were playing a completely different game.
Steam has revamped this system with a feature called Steam Families where you can share games on an individual basis, and as long as two people aren't trying to play the same game, everyone can play concurrently.
We've covered all the most important facts about Steam Families already, so I won't repeat it all here, but before we get into how you can control what people see from your library, you need to enable Steam Families, if the feature is still in Beta when you read this.
Every participant needs to go to Steam > Settings > Interface > Client Beta Participation and ensure that "Steam Families Beta" is enabled. Once the feature is out of Beta, this step won't be necessary.
When you're ready to add family members, you'll invite them to be regular friends first. I recommend using the Steam friend code method. Once you've added everyone meant for the family group, you can invite them to become family members by going to Steam > Settings > Family > Manage your Steam Family.
Invite members from here, you can simply find them on your friends list.
That is, after I show you how to hide your games first.
To test that this actually works, I set up a dummy Steam account and added it as an adult family member to my primary account. This allowed me to check that games were actually hidden from the family member's account.
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