You can look at the documentation online to learn how the advanced search is working 🔎 Advanced Search in Asana: Examples & Best Practices
And you can include filters on the Assignee or Collaborators.
Please note that there is a test in progress where the Advanced Search would not be accessible from the bottom of the search suggestions but instead as an icon (two toggles) at the far end right of the top search field in the app.
Let me know if you find it.