Looking for logging into the Steam Double site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Steam Double site. After that you can login as usual with your login credentials.
https://gaming.stackexchange.com/questions/13762/is-it-possible-to-log-your-steam-account-into-two-computers-at-once
https://support.steampowered.com/kb_article.php?ref=8963-EIKC-3767
https://steamcommunity.com/discussions/forum/1/624076851253548039/
https://forums.tomshardware.com/threads/multiple-pc-using-one-steam-account.2159413/
https://arstechnica.com/civis/viewtopic.php?t=1123321
https://github.com/ValveSoftware/steam-for-linux/issues/3942
https://www.reddit.com/r/GlobalOffensive/comments/7kvuvc/this_script_will_let_you_easily_switch_between_2/
https://www.eurogamer.net/articles/2013-09-11-steam-will-allow-families-to-share-games-across-multiple-accounts
https://www.reddit.com/r/tf2trade/comments/1a8agn/q_how_do_i_run_2_steam_accounts_at_once_on_the/
https://partner.steamgames.com/doc/features/auth
https://www.maketecheasier.com/steam-not-opening-fixes/
https://boardgamegeek.com/thread/1095818/playing-2-steam-games-1-account-or-2-accounts-1-pc