2.5in OD tube ends fit inside your flexible hose and you'd use hose clamps to hold them on.
the other ends fit into the inlet and outlet of the cyclone separator. simply glue them in.
The one with the support rib connects on top of the cyclone's lid.
Print on the elliptical surfaces given on the corners
The author remixed this model.
These are adapters that fit the original model's inlet and outlet ports.