1) You need to be a registered user of Dimdim to start meetings. Registration is FREE and takes a minute. Please see this link for more details:
http://help.dimdim.com/activekb/questions/110/How+do+I+create+a+Dimdim+ID+%3F

2) Login to the Portal MyDimdim Tab
3) Click on the “Start Meeting” link

4) You can invite attendees by entering their email ids in the invite attendee’s field.

5) Select Features. If you wish to share your desktop, please ensure “ Screen share = enable” is selected. This option is currently supported in Windows only & will prompt for installing a browser plug-in.
6) Click on Submit.
7) The meeting console will load – please wait till it loads completely.
8) Your meeting is now started.

9) You can use the settings link on the top right hand corner to modify attendee microphones, and other meeting room settings.