You can read the following articles:
Create a custom page:
https://vborg.vbsupport.ru/showthread.php?t=228112
Templates and registering variables:
https://vborg.vbsupport.ru/showthread.php?t=228078
There is an existing tutorial here in vb.org with detailed steps in creating a mod...will post the link as soon as I see it. Though as far as I can remember it is for vb 3
I suggest you also download an existing mod and check how it works.