There's a lot of information on the internet. If you google you can find the course-manuals from AIDA and others, and here on DB there are extensive articles and forum threads with a wealth of information. Let me link one for you that provides a good starting point:
here it is (click). Read that first, it will give you some basic knowledge so you can browse and search the forums a bit more targeted.
For the practical part of freediving, I'd say if you're still a beginner then you're not much at risk of drowning due to blackout. The biggest risk for you would be to make a practical mistake like swimming too far from shore, getting in a current, not knowing what to do when you get a cramp... stuff like that. You might learn some wrong or sub-optimal techniques and habits, and perhaps you buy some gear that later turns out to be not just it.
Not everyone here did a course, some prefer learning by doing. But if you go that route, do it with a clear head. Read first, then practise what you read about, then read some more. Try not to jump onto new lessons every day, but let your knowledge and experience evolve slowly.
If you go out alone or with an equally inexperienced buddy, stay well within your comfort zone and make sure you keep a good overview of the risks.
If you go out with an experienced buddy, make sure he is fully aware of you not yet being at his level and keep the dives for both at the limit of the least experienced.
