Rosterr needs to know both who you are on Roblox (so it can match you to your group and ranks) and who you are on Discord (so it can message you and verify your login). Every Rosterr account therefore has both accounts linked. You can start with either one.
Signing in for the first time
Open the Rosterr website and choose Continue with Discord or Continue with Roblox.
Approve the sign-in on Discord's or Roblox's own page. Rosterr never sees your password.
Rosterr then asks you to link the other account.
If you started with Discord: link Roblox
Enter your Roblox username.
Rosterr shows a short verification code.
Open your Roblox profile, choose Edit Profile, and paste the code into your Bio / About section. Save your profile.
Go back to Rosterr and choose Verify.
Once verified you can remove the code from your bio. If "Sign in with Roblox" is available on the site, you may be able to link through Roblox's own approval screen instead of the bio code.
If you started with Roblox: link Discord
Rosterr sends you to Discord to approve the link. You can then carry on.
One account per person
A Roblox account can be linked to only one Discord account, and the other way round.
If you see "This Roblox account is already linked to a different Discord account" (or the reverse), you are trying to link an account that belongs to a different Rosterr user. Sign in with the pair you used originally. If you no longer have access to the original account, contact support.
Signing in to a specific workspace address
Business workspaces can have their own web address, such as staff.yourgroup.com. On that address the sign-in page says "Only members of this workspace can get in". You still sign in with Discord or Roblox. After sign-in you are handed back to the workspace address. If you are not a member of that workspace you see "You're not a member of this workspace".
How long you stay signed in
A sign-in lasts about 30 days and is renewed every time you use Rosterr. Signing out ends it straight away on that device. If your workspace has the signed-in devices list (Settings, in your account), you can see and end sign-ins on other devices (see "See where you are signed in and sign out other devices").
Signing in on the phone apps
The phone apps use a slightly different flow. See "Sign in on the phone app (browser sign-in and the code method)".
Troubleshooting
"Sign in with Roblox isn't available right now." Use Discord instead. Roblox sign-in is turned on and off by the Nebula team.
The verification does not work. Check that you pasted the code exactly into the Bio / About field of the same Roblox account you entered, and that you saved the profile. Roblox can take a moment to show the change.
You are signed in but see no workspace. See "Why can't I sign in or see my workspace?".
Related articles
How do I get access to Nebula Rosterr? (waitlist and early access)
Sign in on the phone app (browser sign-in and the code method)