Open the Las Vegas Geocommons API
Select the first layer you wish to add to the map. I suggest that you start with a BaseMap.
Click on BaseMaps
Click on BaseMaps/CLVBaseMap (MapServer)
Select View In: ArcGIS.com Map
The map will open in ArcGIS Online. It may ask you to save it. Give it a name and at least one tag ("Las Vegas" is sufficient)
Let's add four more layers to the map:
Return to the Home screen by clicking on the Home link on the top left of the page.
From the home page, click on PublicSafety, then select PublicSafety/Fire_Hydrants (MapServer)
Right-click on the HYDRANTS layer, and select Copy link address
Return to your ArcGIS Online Map.
On the top left, click Add --> Add Layer from Web
In the pop-up window, paste (ctrl+v) the link into the URL window, and click ADD LAYER.
Although the layer is added, it will appear faded (grayed out) under the contents tab. This happens when the extent of the map is too broad to view the layer, so you will need to zoom in.
Type "Community College Drive" in the search bar, and select the Community College Dr, Las Vegas, NV, 89107, USA option. This will zoom you to our study area, which is the CSN Charleston Campus. Once zoomed in you will see the added layer of fire hydrants appear as dots.
Both the sewer mains and manholes layers are located under Exiting Infrastructure --> SanitarySewer.
The street lights layer is located in PublishedLayers --> Streetlights.
Remember to save your map often!
In the end, your map will look something like this:
As you can tell, there's a lot of data on this map that is unnecessary for your project - pretty much everything outside the CSN Charleston campus's immediate area. Keeping this data will make your file huge and may be confusing for field data collection and presentation.