D&D 5E (2014) Advice on Homebrew creations. characters, races, classes, spells and such.

[Cold Thane]

I'm trying to create my own homebrew campaign. I am running into some difficulties with putting classes and things into stats, numbers and probabilities. I would like help in figuring some of this stuff out if possible.

 

[ccs]

And by "campaign" you really mean "Making an Entirely New Game from Scratch"?

If so, then my advice is to go invest in a copy of Dungeons & Dragons 5e (just the Players Handbook, Monster Manual, & Dungeon Masters Guide), & read that to see how this is done.
Or any other existing RPG since there's no one exactly correct way to make these things....

 

[Sunseeker]

I'm unsure of your question. Are you asking how prevalent certain classes/races/etc. should be in your setting? Ratios are great for that. Or are you asking which classes/races/etc. you should include as playable?

Or as you asking how to make all of those things from scratch?

As much as I enjoy creating campaigns, I wouldn't attempt to make a D&D-like game myself. Too much work when suitable products already exist. And there's plenty of clones with plenty of variations on the subject.