Usually its a yr and a day of training, but thats like of coven regulations.
I find that since theres soo many areas to work on, one needs to start with one and focus on that for a few months till they know it down and can practice it with ease(and then either continue at the basic lv or intensify the training to improve).
I've learned from personal experience, trying to learn many topics at once leaves you only with many books only partially read. You end up spreading yourself in a number of directions that nothing actually gets done, especially if you do it along normal teachings such as school, work and everyday life.
Also, not all spells on this site are real or actually work. Some of them you have to tweek them, and others you have to just feel if it feels right to you. Best bet, just learn how to create your own, they'll be the most powerful spells you could cast cause they come with your full intent and desire.