As a registered user, you are able to create groups.You simply go to “My groups” on the left sidebar, and click the button “Create”. You can name your group, choose which type of organization it is from a drop down menu, and create its personalized description.
You might want to change the cover image of your group page. To do that simply navigate the cursor to the top area of the page where you see the map. Upon that action, the blue "Change cover" button will appear. Click the button, choose a picture on your computer to upload, crop it and hit the "Save as profile picture".