For finding a scheme, from within the main admin area, you have a couple of options. The primary way would be to search for the scheme directly from the 'Neighbourhood Watch option in the menu:
From this page you can then search for any scheme name and find schemes:
To find all schemes in an area, you can use the options button for any of the areas on the Neighbourhood Watch screen, then choose 'load schemes for area':
You can also find schemes from directly within a coordinator account, from the 'scheme' tab when editing a user account, or from the full editor page:
You can then view and edit the details for the scheme from the pencil icon.
For mapping the scheme's area you can click on the map to create points until you have an enclosed shape that encompasses the scheme area. On this map you will also see grey outlines of any existing schemes in the area.
From this screen you can change any of the details for the scheme as above, including approving the scheme, as detailed here.