Really don´t exist a certain tutorial about this tool, in other post i put you any general steps for implement this tool. Are this:

Insert simply must push RTC (Real Time Clock), then you will change each season, when you have configured to your liking, push Insert DNS and then finally modified the hours of day and push it to Insert.

Then to see the results you emulate your hack to VBA, with the No$GBA are no changes in dns.

Finally, put pokes day and night is a matter of ASM, a rather complicated language (in my opinion).

I am sorry by i can´t help you.

Salu2.

EDIT: This is my tuto about DNS, i hope that it helps you Tutorial DNS