If you had a SmartThings account prior to the 2.3.5 app release, you almost certainly have a SmartThings account. If you created an account after the release of 2.3.5, you likely have a Samsung Account. Lastly, there is the possibility of having a SmartThings account and a Samsung Account with the same email address. This is the most confusing scenario which should be addressed soon.
Here are the steps for each of the three scenarios in order of likelihood.
SmartThings Account Sign In
a. Click Login
b. Enter your SmartThings email address:
c. If you only have a SmartThings account, the login will detect that and prompt you for your SmartThings password:
d. Enter your password and sign in
Samsung Account Sign In
a. Click Login
b. Enter your Samsung Account email address:
c. If you only have a Samsung Account, the login will detect that and prompt you for your Samsung Account password:
d. Enter your password and sign in
SmartThings or Samsung Account Sign In
a. Click Login
b. Enter your email address:
c. The login will detect that you have a Samsung Account and SmartThings account and will prompt you to select which one you would like to sign into:
d. If you have both accounts, your Hub is likely claimed on your SmartThings account and you will want to choose that. If you choose SmartThings, you will be prompted for your SmartThings password:
e. Enter your SmartThings account password and sign in.
f. If you choose Samsung Account, you will be prompted for your Samsung Account password:
g. Enter your Samsung Account password and sign in