Step 3: Gather Your Login Information
The Nexus Android Marshmallow installation process will ask you for various login information (Google account, email, Wi-Fi, etc). The update might also log you out of various applications on board your Nexus phone or tablet. You'll want all of this information handy.
If you haven't had to login for awhile, there's a chance that you've forgotten your passwords and user names for various services. You'll want to track that information down before you install so that you're not wasting time during or after the installation process.
It's a simple step but it's one that could save you a lot of time, especially if you use a ton of apps and services on your Nexus device.