Once logged in, you can navigate through the CMS to perform edits OR surf the regular site in that browser where you should now see a black BigTree bar at the top of your window allowing you to jump directly into edit mode on any page you have permissions for while browsing the site.
If you don't want the whole black bar open all the time, you can click the X on the far right of the blue bar (not shown in this image) to minimize the bar to show just a black tab with the BigTree icon. When you find a page you want to edit, just click the tab to expand the bar, and then choose if you just want to edit the content in place, or if you need to open the whole page in BigTree for more complex edits.
The EDIT CONTENT option is a good option for making quick edits to the basic content of the page, as it pops open on top of the live website and gives you access to the 7 basic content fields of the page.
The EDIT IN BIGTREE option opens the page in full edit mode in the CMS, just the same as if you entered edit mode from within the CMS, and gives you access to everything you have permission to change about a given page. This is the better option for any edits longer than a quick fix.