So, you can use Google Drive as a back up service to make sure that all you documents and photos etc. are kept in the cloud rather than just on your computer.
You can log into your Google Drive on a browser on your tablet or on your computer. It is simply one of the features available with your gmail account.
If you download the app onto your computer, then a copy of all the documents will be synchronised between the cloud and the computer. If you do not do this then you can simply drag your files onto the drive in the cloud. Provided they are not already infected, it is not possible for the ransomware to get access to these files. If your files are synchronised you can still restore them to a previous version. Open the document, click on file and choose previous versions. Google will keep versions of files for 30 days.
If you have the app on android, it only gets the files from the cloud when you open them and so nothing is affected if your google drive isn’t synchronising with a computer.
This is similar to Dropbox which on the free version automatically keeps version for 30 days.