1) extract the .rar to your desktop

2) add the .jar you are working with inside the extracted folder

3) copy the full name of the .jar you are working with, including the .jar part

4) right click on the 1.bat and select edit with notepad++ (install it if not already done)

5) replace Trebuchet.odex with the full name of the .jar you will be working with, then save and exit

6) double click the 1.bat to decomple your .jar, the result will be the classes folder

7) after making your edits double click the 2.bat, this will recomplie the outcome will be a classes.dex

8) right click on the .jar you where working with, select 7zip / open archive

9) drag and drop your new classes.dex inside