1) Backup your P6 database

a) Log as SA into your Servername in SQL Server Management Studio
b) Expand database folder
c) Select your database --> Right-click on your database --> Tasks --> Backup
d) Choose your database, backup type, backup component and destination in General page
e) Click OK

2) Add the users manually in your new SQL Server

a) Expand Security Folder --> Right-click on Logins folder --> New Login
b) Add a new user pubuser in General page
c) Choose SQL Server Authentication
d) Type and confirm a password for pubuser
e) Uncheck Enforce password policy
f) Uncheck Enforce password expiration
g) Uncheck User must change password at next login
h) Click OK
i) Expand Security Folder --> Right-click on Logins folder --> New Login
j) Add a new user privuser in General page
k) Choose SQL Server Authentication
l) Type and confirm a password for privuser
m) Uncheck Enforce password policy
n) Uncheck Enforce password expiration
o) Uncheck User must change password at next login
p) Click OK

3) Restore your P6 database in your new SQL Server

a) Log as SA into your Servername in SQL Server Management Studio
b) Right-click on databases folder --> Restore a Database
c) Type the name of the database that you want to import in textbox To Database
d) Select From device --> Click on ellipsis button --> Add --> Browse your backup file
e) Check Restore checkbox of your backup.

4) As SA in SQL Server Management Studio, run sync script for all users

a) Run the following queries to resync the public (ex: pubuser) and privileged users (ex: privuser):

exec sp_change_users_login 'Update_One','pubuser','pubuser'
exec sp_change_users_login 'Update_One','privuser','privuser'