Who can do magic?
As interesting and story-fueling as it is to say a witch is born not raised, it's a blatant lie. For 99% of people, magic is a skill that can be learned. Of course, some people are naturally better at it than others - just like how some people are better at math, and some people are better at music, and some people are better at sports. But even the most mundane human being could do some basic magic, if they took the time to learn it - and took it seriously. (After all, for newcomers, the greatest challenge of learning magic is usually accepting that it's actually real.)

Do Magic and Technology get along?
Yes. Well, sort of. For the most part, magic and technology tend to get along just fine. Great, even! If you know how to do it, you can use magic to keep your phone alive longer, or to jump your car, or to run your heater. After all, magic is pretty much just energy. Easily manipulated energy with funny properties, yes. But energy nonetheless. And, just like a power surge can kill your electronics, too much magic around technology can - you guessed it - kill your electronics.

So, basically, your video games are just fine, so long as you are capable of controlling your magic from creating massive energy spikes. And that means no lightning bolts in the house.

How's it work?
As stated above, magic is just a kind of energy. While we don't know terribly much about how it works, we do know that it seems to be heavily influenced by the mind. This is why belief is so important, why wizards tend to collect books of spells, why the items used in magic always seem to have some sort of intellectual or emotional significance to them. Just like our actions in life, magic can be quite powerful when fueled by our knowledge, and unruly when fueled by our emotions.

They say that knowledge is power - and in the case of magic, that is literally true. The greatest magicians tend to be the ones with vast amounts of knowledge. Minding, of course, that lists of spells aren't always the important knowledge. The better you know something - person, item, process, whatever - the greater your ability to affect or control it.