You should still be able to create the bucket categories, they are not specific to any filters or fields.
Then you'd create a breakdown source and use the Bucket group you created for the facts table in the breakdown source.
You'd then create an indicator source and then the indicator - point it to the indicator source and add the breakdown that's using the bucket groups. You can add your specific filter at the indicator level.
I know there are a lot of pieces to this and it took me months to grasp this.
1. create bucket group
2. create breakdown source (facts table = the bucket group)
3. create breakdown based on the breakdown source
4. create indicator source
5. create indicator - add your filter for the incidents you want to see - and add breakdown
This might help too: https://docs.servicenow.com/bundle/london-performance-analytics-and-reporting/page/use/performance-analytics/concept/c_BucketGroups.html
