Our demo user here, Bob Kelly, has a check-mark in the Office Professional Plus license. This means he will be able to sign-in with the new Office 365 ProPlus and activate it against his service.
We set up our Office Licensing Service so that any user who has been assigned a subscription license to Office Professional Plus has a license to the new version of Office, Office 365 ProPlus. It doesn’t matter whether your tenant has received the service upgrade or not. This includes Office for Mac 2011 for Office 365.
The second step is installing Office 365 ProPlus. If your tenant hasn’t been upgraded yet, you won’t have access to the installer from the Microsoft Online Portal. Instead, you will need to either install Office 365 ProPlus from a Trial account, either a Midsize Business Trial, or an Enterprise E3 Trial, or use the Office Deployment Tool. If you install from a Trial account, you will sign-in by using your organizational account when you first run Office 365 ProPlus after the installation. This essentially deactivates the trial on the computer and reactivates Office 365 ProPlus in your production tenant.

You have two main options:
Installing Office 365 ProPlus from a trial account:
This is the least technical way to install Office 365 ProPlus but require more steps and clicks, best for a business user or small business without IT help. You will create a throw-away id to sign up for the trial. After the installation, you sign in to Office 365 ProPlus by using your organizational account. Be sure to follow the instructions step by step.
Installing Office 365 ProPlus using downloaded source files:
This way requires working with config.xml in NotePad and command-line tools, but has fewer steps and can also provide more flexibility for an IT professional who wants to have the Office 365 ProPlus source files to install Office on multiple machines through a network share or other software distribution system. See Installing Office 365 ProPlus using downloaded source files.

Source: Microsoft