Selecting and unselecting layers

When using Caltopo on Google Chrome Browser, I do not see options to view and select or unselect layers in the MapBuilder Topo option. Ideally, I'd like to use either the basic topo or Global Imagery with ONLY river/ scream name overlays, and NO roads or businesses. All I can see is to have Global Imagery with no labels at all, or the MapBuilder which is way too much information. How can I unselect roads? I tried to search this on Google and FAQs and no instructions that I followed led me to being able to do this. Thanks