Download to Google Drive so long as it's under 15gb (which is what Google gives you, anything more you must pay for, similar to iCloud.)
- Click Download Backup and Sync
- Read the Terms of Service and click Agree and download.
- After it’s downloaded, open InstallBackupAndSync.dmg.
- Move Backup and Sync to your Applications folder.
- Open Backup and Sync. (If you see a warning that "Backup and Sync is an application downloaded from the Internet," click Open.)
- Sign in with your Google Account username and password.
- Choose your sync settings and click Next.
Now my advice would be to make sure you enable Two Factor Authentication on Google Settings. After you do this, add the addition of your 8 digit backup codes to verify identity. Then, place these codes in a place you will never lose them! Digital and even a hard copy would be best.
This extra step will ensure your data is more secure while also ensuring you are able to regain entry if you lose your phone and cannot verify in any other ways.
Hope this helps!