docs: update docs/developers/build.md to make it clearer

- Improved clarity on what each method is used for.
- Deleted the suggestion to install Go. This is no longer required since
  we use rules_go in Bazel now.
- Changed the order of the methods since people going here will most
  likely be devs.

Change-Id: Ifcbbba9a1c82f7b51383b4d042f0ff8b6a6a6964
diff --git a/docs/developers/build.md b/docs/developers/build.md
index 90c9564..0098b54 100644
--- a/docs/developers/build.md
+++ b/docs/developers/build.md
@@ -1,37 +1,41 @@
 # Build the extension
-A zip file with the contents of the extension, which can be uploaded to the
-Chrome Web Store and addons.mozilla.org, can be created by following these
-instructions. (make sure to [install Go](https://golang.org) before building the
-extension, as it is needed during the build).
 
-The last section explains how to build the extension automatically when you
-change the source code.
+Building the extension is the process of transforming the source code into a
+bundle that can be loaded into the browser to install it.
 
-## Build the extension as a zip file
+There are 2 ways to build the extension depending on your use case.
+
+## Build the extension continuously (for developers)
+
+Run `make serve_chromium` (for Chromium) or `make serve_gecko` (for Firefox).
+
+This is useful if you're developing the extension and want a fast way to
+quickly test the changes you made to the source code to verify they work
+correctly.
+
+These commands will run bazel-watcher and continuously serve a fresh version of
+the compiled extension at `dist` whenever you make changes to the source code.
+You can load this folder in Chrome by going to `chrome://extensions` and
+selecting "Load unpacked". In Firefox, follow [this
+guide][firefox-unpacked-pkg].
+
+Keep in mind that while the extension is continuously built, it is not
+automatically being loaded into your browser. You'll have to reload the
+extension manually whenever `dist` changes (but at least you won't have to both
+build and reload it).
+
+## Build the extension as a zip file (one-time)
+
 Run `make release` to build the extension for all the available channels and
 browsers. You can also run `make {target}` where `{target}` is one of the
 following: `release_chromium_stable`, `release_chromium_beta`,
 `release_gecko_stable`.
 
-Run `make clean_releases` to clean all the release files (this removes the `out`
-folder, which is where the release files are saved).
+This is useful if you want to upload a new version to the Chrome Web Store or
+addons.mozilla.org, or otherwise want to build the extension manually into a
+`.zip` file.
 
-Take a look at `Makefile`, you'll find other targets for _make_ which do other
-interesting things (like `clean`, for instance).
-
-## Build the extension continously
-If you're developing the extension, you might want to load it into your browser
-without having to constantly build it manually after each change. In order to
-do that, you can run `make serve_chromium` or `make serve_gecko` depending on
-the type of continuous build you want.
-
-This will run bazel-watcher and continuously serve a fresh version of the
-compiled extension at `dist`. You can load this folder in Chrome by going to
-`chrome://extensions` and selecting "Load unpacked". In Firefox, follow [this
-guide][firefox-unpacked-pkg].
-
-Keep in mind that while the extension is continuously built, it is not
-automatically being loaded into your browser. You'll have to reload the
-extension manually (but at least you won't have to both build and reload it).
+Run `make clean_releases` to clean all the release files (this removes the
+`out` folder, which is where the release files are saved).
 
 [firefox-unpacked-pkg]: https://extensionworkshop.com/documentation/develop/temporary-installation-in-firefox/