Flex duct is exiting from above the rectangular duct rather than from the side

[Anonymous]

When I add a 8 inch round flex duct to the side of a 12"x14" rectangular duct, the process creates a joint with some duct fittings but the flex duct comes from the top of the rectangular duct rather than from the desired side.

Any advise how to make the round flex duct come out from the side?

Also, related question, before you add the round flex duct to the side of the rectangular duct which does not has a connector on its side, do anything needs to be added (like a joint? or anything else?) before adding the round flex duct?

The round fled ducts are normally added to connect to the ceiling diffusers.

Thanks in advance.

[RobDraw · Accepted solution]

I usually have a piece of hard duct before the flex. This will help with the connection issue also.