I am on Certblaster site and I need help to access the labs part of MCSA installing and configuring Microsoft Windows Server 2012/R2 70-410.
If you used their services and bought one of the available packages, then I recommend you access the website and log-in. They should have just created a username and password based on your purchase.
This is the only way to access the tests you have purchased because there is no other possibility.