A Beginner Guide to DECORATE?

HELLO, I am new to modding Doom, and interested in learning DECORATE, to make weapon mods and such. Especially for games like Heretic and Strife because they are not paid much attention to by modders! I went to the zdoom wiki like some have said to, but, it seems more like a dictionary for those who already know how to use DECORATE and are not just starting out. I open up other peoples mods & try to figure out how to code DECORATE, but that is not helpful
So I have 2 questions:
1.
Is DECORATE the first thing I should learn to do for Doom modding, or should I learning something else first?
2.
Is thare anything like a Beginner Guide to DECORATE, that explains what walks you through making different stuffs?
Hopefully something I can use offline, so I do not have to bother you guys every time I have a simple question or problem
and then figure it out on my own.
Also, I see people talking about how modders do not use PK3 properly, and that makes inefficient archive? Where would I go to learn to do it right?
Apologies if this is not the right section, I thought that a Guide to DECORATE would be a type of Resource.
So I have 2 questions:
1.
Is DECORATE the first thing I should learn to do for Doom modding, or should I learning something else first?
2.
Is thare anything like a Beginner Guide to DECORATE, that explains what walks you through making different stuffs?
Hopefully something I can use offline, so I do not have to bother you guys every time I have a simple question or problem

Also, I see people talking about how modders do not use PK3 properly, and that makes inefficient archive? Where would I go to learn to do it right?
Apologies if this is not the right section, I thought that a Guide to DECORATE would be a type of Resource.