Hey Wilson,
For retrieving the owner of the object, you have to make sure that ' store the owner ' option is checked in the entity.
Then while retrieving the data us the constraint,
[System.owner='[%CurrentUser%]']
Pls refer to the following doc also, for the manager to see their own data.
https://docs.mendix.com/refguide/access-rules/
If I am confused in your question, please let me know.
Hope it helps!