On Desktop
At the startup screen, click Sign In and then Restore From Recovery Phrase.
Enter your recovery phrase into the text box, and select a new display name.
Your Session ID is recovered.
On Mobile
At the startup screen, tap Continue your Session.
Enter your recovery phrase into the text box.
Enter a new display name and tap Continue.
Select your preferred push notification setting and tap Continue.
Your Session ID is recovered.
To learn about account recovery, check out this video: