Add some docs

README.md

@@ -10,9 +10,32 @@ Read more about the usage and associated tools at https://aras-p.info/blog/2017/
 
 ## Hookup
 
-Call `register_thread_with_profiler` for each thread.
-
-Call `write_profile` when you need to save the results.
+Call `register_thread_with_profiler()` for each thread.
+
+Call `profile_scope!("what you are measuring")` for each scope to profile.  Will introduce a hidden variable that stops the profiling of the section when going out of scope.
+
+Call `write_profile(file_path)` when you need to save the results.  Make sure all profiles introduced with `profile_scope!` are actually out of scope.
+
+## Example
+
+```rust
+thread::spawn(|| {
+    register_thread_with_profiler();
+
+    {
+        profile_scope!(format!("Thread {:?}, section {:?}", 1, "init"));
+        // your "init" stuff goes here
+    } // profiling scope ends here
+
+    {
+        profile_scope!(...);
+        // and so on
+    }
+});
+
+// at the very end, after joining all threads
+write_profile("/some/place/for/your/profile.json");
+```
 
 ## View results