Have on of those range hood that is convertible. Duct or ductless. Mine just re circles
Air into a filter. Problem is on the front of the hood, there are vents, and air is coming out.
When it is running and not going into the filter.
I think those vents are for duct work setup. What to do?

Most good range hoods are vented to the outside. I have one like yours, and the filter just gets greasy. When I do my kitchen make over I am going to make sure I have it vented outside. Mine is like yours, vent on the outside and a filter inside.

Tick

The air has to go somewhere and the vents in the front are for that purpose. The fan picks up the air from the renge, it is sucked through the filter and then blown back through the front vents. If you can feel air being sucked in, it is working properly. If you do convert to a vented hood, you gat a plastic trim piece that blocks the front vent holes.