Follow the prompts. Flanges can be up, down, different sizes, etc. If value entered is negative than a down flange is drawn. If a zero value is entered then no flange is drawn. Reliefs can be different sizes, or no relief if desired.
Negative value draws flange to inside of pan, Positive to outside.
Linetypes are chosen for up flanges. For example if you use linetype 3 for O.D. flanges on up bends then down flanges will automatically have line-type 2 lines or vise a versa. All lines can be drawn with line-type 1 if desired, then you can manually change those that you want. A check is done to see if two or more return flanges will interfere with each other. If this is the case then a prompt will ask you how those corners are to be drawn.