Here is how you can add WMS layers into your Maps site:

1. Open the LAYER ADMIN panel. 
   
2. Click the "NEW LAYER" button at the bottom of the screen.
   
3. In the 'Create a New Layer' dialogue, click the "NEW WMS LAYER" button.
   
4. Paste the URL for the WMS layer into the field "WMS URL". Also, be sure to give it a name.
   
5. Click "LOAD".
   
6. Select the layer within that WMS file that you wish to use.
   
7. Select the style that you wish to be applied from the list of presets that are coming from the WMS source you are pulling into Lightship.
   
8. Click "SAVE". 

That's it! Your WMS layer is now in your site.

As a side note, if you are looking for a great source of WMS open data for British Columbia, check out DataBC.