like in the title im new to modding I do have some experience to java but not to Minecraft codding 
I want to create a mod that add stats to minecraft something like playerex
I would like if you can give me some tips to help me understand how do code for minecraft i tired youtube tutorials but they dont explain what they do so I cant replicate it  

so my main questions are:
How can I get accustomed to minecraft method and way of coding

how to create and deal with GUI ?

and how to deal with the client server interactions with java?

the importance is Most to least important?

Thanks for the helpers and I hope this post help other beginners 

I would suggest looking at the literal documentation.

Honestly, my method to learning anything is to "mess around and find out". Literally just pick something you're interested in modding and start looking at the Forge docs along with the work environment's external libraries. From there start building something and test to see what happens. It's really the only way to truly understand how it works. Yes, those video tutorials are okay for a starting point but at some point you'll need to go eyeballs deep on your own.

Be willing to explore and experiment. Be willing to be okay with stuff crashing and learning from it. Give yourself permission to be a beginner and student. Short of taking a hammer to your computer, you're not going to actually break anything by doing any of this. Not sure what else to say here.