over 4 years
ago -
Avanya
-
Direct link
Your friend has to activate Family Sharing in options while logged in. That allows their library on that computer to be shared with other accounts.
https://support.steampowered.com/kb_article.php?ref=3784-QLBM-5731
https://support.steampowered.com/kb_article.php?ref=3784-QLBM-5731