Update 1.2_Setting_Up_Testing_Environment.md (#10)

- navigation integration for 1.2_Setting_Up_Testing_Environment.md

Author: jeremiah-louis

1_Getting_Started/1.2_Setting_Up_Testing_Environment.md

@@ -67,6 +67,6 @@ This will execute all tests in the test directory. You should see a message indi
 ### Conclusion
 Setting up a testing environment for Dart is straightforward, thanks to its well-designed tools and packages. Now that you've laid down the groundwork, you're ready to dive deeper into the world of Dart testing.
 
-In the next section, we'll explore the basic structure of a Dart test. Onward!
+In the next section, we'll explore the basic structure of a Dart test. [Onward!](./1.3_Basic_Test_Structure.md)