From the Money Tab (bottom left), you will see your Buckets listed starting with your Core Account Bucket.

To put money into an existing Bucket, tap on one of the existing Buckets from your list and then tap 'edit' on the top right hand side.

From the Bank Icon screen, you can also tap on "New" to create a new savings Bucket or you can tap on "Manage" to select the Bucket you want to make changes to.