1. Compile the package in your local.
2. Check whether the procedure is in the package specification, else, add it to the package specification.
3. Go to the object browser, find the respective package, right click and select view and edit.
4. It will open the package in a PL/SQL window.
5. Browse the left panel to see the procedure in the package specification, right click and select TEST.
6. It will open a test window and load the required package.procedure inside a BEGIN-END block.
7. Provide the required parameters in the test window.
8. On top, you would see the DEBUG option.
9. DO NOT click on EXECUTE button. Click the debugger button.
10. It will load the package.
11. Click STEP IN, which looks click a right turn sign.
12. It will let you debug line-by-line.
13. you can STEP OVER the lines you are not concerned.
14. Once you reach the line you want to test, select the variables that you want to see the values at run time.
15. You need to keep using the step in until you are done with debugging.
16. Once you reach END, the test window will execute the procedure.
17. If, point 15/16 fails, it means you got an error at that line number and you will automatically come out of the package.