As in use the IExtendedProperties and events to manipulate the properties?:
I have heard of IExtendedProperties but i'm currently not using it, is it the thing I need to add multiple skills that you can level up? I currently only know how to give the player the ability to level up one thing instead of many skills.
What do you mean by only modifying one skill?:
Not sure if I understand what you mean, sorry if I worded this oddly... I am still very new to modding, and am having a hard time explaining my situation. But was talking about as in vanilla minecraft there is only a single thing that you can gain experience for, how to add I multiple things to gain experience for?
I'm really trying to make something like this http://www.planetminecraft.com/mod/chaoscraft-2849881/