Need help making my AddOn (first addon ever)

Hey, this would be my first addon to be made and I really don't know where to start. I made a image in PS how I want it to look like, but where to start?
I could do some XML and lua tutorials, but I also read that you could do only XML or only LUA for a complete addon - LUA being less Memory Using.

This is my image:


It may ofcourse look a bit different, depending on whats the most user friendly and neatest. But thats not the real issue.

I could tell what I want to make:
The main idea is that you can make pieces of text (like when you create a macro with "/g Hey guildies " and use the button every time you log in or such) and then are able to select one (on the left list) and click "Send" to send it into your chat.

The functions shouldn't be to much of a problem, but I always find those outdated tutorials and stupid IDE's (*cough*WOW Addon studio*cough*) that don't do what I want and output messed up code where I don't know what I actually did...

So anyone knows where I could possibly start with a GOOD tutorial. I'd rather write it completely in LUA but I don't know if that's the smartest to do.

I can create simple apps in C++ and Java, but I'm not experienced

Thanks in advance

~Deep92