What is the preferred program for finding asm code in the roms? I can't figure out how to find the code for events using create or update codes as addresses.
You can view code when using some sort of a disassemble program. For example some come with the emulator/debugger.
Here a link for No$GBA (Make sure to grab the debug version) https://www.nogba.com/
This can be used to learn how a game works but you also need some background on the hardware.
Here are great resources about GBA: http://www.coranac.com/tonc/text/toc.htm
DSvania does have ARMIPS setup and ready to use and you can patch games within the editor. The ASM files are in the so named folder in the editor directory and are a great source to see some examples.
When you speak about event code do you mean the event data table for levels? This one could probably be figured out without knowing to code. You could save the ROM change a event a bit build/save the ROM again and compare the two files with a hex-editor like HxD to find the offset of the change. Then you can toy around with this values within the debugger to figure out more what this values are about. It is really not clear what you try to do based on your question but I hope this will give you a idea.
I have a question too.
Are there guides/tutorials for DSvania?
Like Video guides on Youtube to do some particular task?
Or general PDF/Text guide how to change a room or two that will go through the tools and tell step by step what to do? May be give away/inspiration of ideas what could be done. (I know LagoLunatics Github does have a good overview about the tools)
Guides around other GBA/DS tolls that can be used for the CV games?
I think a guide can be a good starting point to give a user a overview about the possibility or give a head start over some frustration barrier of learning.
Also I am not sure if LagoLunatic is ok with posting such thinks here since the thread is about the editor and when there are tutorials it could go into a other Page.