Calculating your BRM will tell you how many calories you need to maintain your current weight. Here is a link to a quick BMR calculator:http://www.myfitnesspal.com/tools/bmr-calculator
Since it doesn't take into account your activity level you may need more. If you plan is to gain weight then you will certainly need more calories a day than what your BMR suggests. But it should give you a baseline to start working from.
As far as protein guidelines go I suggest reading this article by Ginny Messina who is an R.D. http://www.theveganrd.com/2013/01/staying-strong-on-a-vegan-diet-protein-and-muscles.html
And for overall eating guidelines I would use this:http://www.theveganrd.com/food-guide-for-vegans
Lastly I would suggest picking up the book she and Jack Norris wrote. Is will tell you about everything you need to know about being vegan and contains sections for athletes.