Need help with finding lines

hey this is the first time i try to make a client

so im using the ROTMG All in One Tool to code and i found out how to decompile it and find the files i need to edit but how do i know witch line is the right one to change?
lets say i want to do this

Line: 1529
On new line:
do i have to find the line and below it i put this code in?

and if there is a better program i can use
and can i use codes from previous builds? like 17.1?

#1 yes
you go to line: 1529, press return to create a new line, here add your code.

#2 no
[Quote: From old post]
you can't simply copy paste 15.0 codes into a 16.2, for a couple of reasons:

#1 code names are different (unless of course its a 'pushtrue' or 'returnvoid' etc in which case #2)
#2 the line(s) at which the code is pasted will be different

ok but how do i find the line? note pad dosnt show you line numbers and if i search with CTRL+F line: 1529 nothing will show

That is where intelligence and experience comes into play. A lot of it, at the beginning, is done by looking at a vanilla version of the client from last patch and comparing where you placed the codes last patch into this patch. Use one of the mod selectors, they come with everything you need (vanilla copy of the game, + the code lines).

After that, its all up to you. Each of us have our own little tricks (or tools) to update each patch that makes it faster. Now is where you get to develop your own.

If you're using line numbers for an old client, decompile the old client, look at where the line number is supposed to be added. Then find that same spot in the new client and you'll have your new line number.
Use notepad++ instead of just notepad as it makes it easier to work with line numbers. If you use windows, use astrogrep to quickly search for things inside the decompiled flash code. When you're looking for the same spot in the new code as the old code, you need to search for unique things that only show up in file you're working with. Programs like astrogrep make that easy.
For many hacks, there's more to update than just a line number.
I suggest you look up some more tutorials until you have a better understanding of how to do it.