Steps to add your robot on Robots page
Let's assume we're adding a robot called "WorldpeaceBot" to Robots page.
(If you're first time ROS wiki contributor) Create ROS wiki account if you haven't done yet. Then ask on this github ticket for your wiki account to be added to a wiki user whitelist (to be distinguished from spammers).
Create your robot page. On your web browser, open http://wiki.ros.org/Robots/%YOUR_ROBOT_NAME% (in our case it'll be http://wiki.ros.org/Robots/WorldpeaceBot). If the URL hasn't existed (which we expect), then you'll be prompted to create one (as the screenshot below), with a list of available wiki templates. Click RobotOverviewTemplate.
Page http://wiki.ros.org/Robots/WorldpeaceBot should be now created with a skeletal content that's automatically generated by the template. You can now freely fill in or modify the sections, add pictures and movies. See existing examples (e.g. Robots/PR2, Robots/TurtleBot).
Then add your robot in the Robots#Portals section. Click "edit" link on the Robots page, add a line for your robot using the existing macro:
<<RobotEntry(%MAKERNAME ROBOTNAME%, %FULL_URL_IMG_YOUR_ROBOT%, Robots/%YOUR_ROBOT_NAME%)>>
Macro RobotEntry's argument:
1st argument is a set of maker and robot's name. It's becoming a convention in Robots page to call a robot from its maker/manufacturer's name first, then robot's name.
2nd argument is a full path to an image of your robot. If you don't have an image online, you can upload one to Robots wiki page from this link.
3rd argument may seem tricky, but it's a link to the robot's ROS wiki page you just created in the earlier step. It's just that the portion http://wiki.ros.org/ is omitted (generally on ROS wiki, you can omit this URL body part when you refer to other ROS wiki pages).
<<RobotEntry(Awesome Garage WorldpeaceBot, http://dummyurl/dummy.jpg, Robots/WorldpeaceBot)>>
More concrete, existing sample (you can see how this gets rendered in Robots#Portals section, find PR2):
<<RobotEntry(Willow Garage PR2, http://ros.org/images/installation/pr2.jpg, Robots/PR2)>>
You are also encouraged to add a link of your robot to one or more sections at Robots#Complete_Listing. This helps people not just to discover robots per their needs, but also to know which type of usecase ROS is used more/less.
NOTE Please respect the alphabetical order when you insert the link of your robot, to avoid any possible conflict.