I don't yet see where you exactly stuck and why .
SAP cannot create a new program itself in your system by implementing a SAP note. You need to help SAP a little bit. you have to create an empty source for the program, then when you implement the note via SNOTE transaction, SAP will add the code for you.
So you just go to SE38 and enter Z_RPRGN_WRITE_CHANGE_POINTER and click create and then save it
next you go into SNOTE and implement the correction .
if you actually click the hyperlink with the correction number, then you get the coding in another window. As it has only a few lines, just copy and paste it to your empty source in SE38 and you are done , this probably much quicker then the extra step with SNOTE.