How exactly does one enable Family Sharing on Steam?

Question

Steam's documentation about Family Sharing (this and this) confusing, sometimes with respect to what happens on the borrower's side and what happens on the lender's side. Besides, it has generally incomplete instructions. The Steam client's settings page for Family Sharing is similarly confusing, and does not clearly separate lender's actions and borrower's actions.

For the sake of completeness, assume there are two people, Alice and Bob, with steam usernames Alice and Bob respectively. Alice's computer is called Alpha and Bob's computer is called Beta. Alice wants to share her library with Bob. That is, Alice wants Bob to be able to play games in Alice's library, on Beta, with Bob being signed into Bob's account on Beta. I hope that is clear enough.

How exactly do Alice and Bob go about doing this? Please avoid phrases like "your account", say "Alice's account" or "Bob's account" instead. And for each instruction, please be clear about whether it is happening on Alpha (Alice's computer) or Beta (Bob's computer).

Answer 1

Authorising Devices for Sharing

Authorising Devices for Sharing

Before authorising other accounts to access your own library, you must first authorise any devices on which others will play your games. This will require you to log in to those devices with your Steam account, so it's important to emphasise that you should not share your Steam account password with anyone under any circumstances.

To authorise a device, in the Steam client, open Steam > Preferences in the menu bar (Steam > Settings on Windows) and select the Family tab. Then, click the Authorise This Computer button. You can then log out of that device.

Authorising Accounts for Sharing

Once you've authorised a device, you can authorise accounts to access your library on that device. Before you can do this, ensure the person, with whom you want to share, has logged into the Steam client on the chosen device before.

To authorise a new person open Steam > Preferences (Steam > Settings on Windows), select the Family tab and tick the box next to their Steam community name. Click OK to confirm this.

Once this is done, Family Sharing is fully enabled and authorised for the chosen account. All the games in your library will now be visible in your friend or family member's library, with a tag to note that it's being shared by you.

To launch a shared game click the same Play button as per normal, owned games. When the owner of the library launches a game, however, the sharing person will be prompted to save their progress (when appropriate) and quit within five minutes. These prompts will appear on a minute-by-minute basis before automatically quitting.

Original Source

Answer 2

If Alice wants to share her games on Alpha, with Bob on Beta, Alice will need to enable Family Library Sharing.

First be sure Alice has Steam Guard security enabled via Steam > Settings > Account in the Steam Client. Then, enable the sharing feature via Settings > Family (or in Big Picture mode, Settings > Family Library Sharing)

Alice can now specify that she would like to share her games with Bob.

If Bob wants to play Alice's games, he will need to ask for her to authorize him.

Enable Steam Guard on your (Bob's) Steam Account. Then, once your (Bob's) account and a computer (Beta) have been authorized by the lender (Alice) following the steps above, simply log in. In your (Bob's) Library, you (Bob) will have access to install and play any of the lender's (Alice's) games on this computer (Beta).

I hope that clears it up for you.