I already told you, Datastore2 is not the official Roblox datastore. It is a user made module.
Look at the Roblox wiki for DataStoreService
Datastore2 is great if you know how it works, otherwise I would get a basic understanding of the Datastore service.
Datastore2 is great because it caches everything and auto-creates backups and has tons of support for serialization and such. If you really want to use Datastore2 I believe their method is :Set() (or :Increment() if it’s a number ) and you only need GetTable({}) on the first call to set default values.