Alright, let's start with some basics.
In hydroponics systems, you use nitrate solutions. Nitrates are plant-ready and water-soluble. You don't need bacteria to convert ammonia and urea-based nitrogen sources into nitrates, like you do in soil. Your main nutrients are Nitrogen (N), Phosphorous(P), and Potassium(K). In most of your garden-store variety shops, you'll find powder fertilizers that have mainly urea and ammonia sources of N , and plenty of nitrate forms of P and K. These types of fertilizers are near-useless unless you modify them by adding other nitrates to boost the immediate concentration of plant-ready N. Not a really viable method economically, but if you've already got a large stock of regular fertilizer, buying some nitrates to add in with the mix might save you a trip to the hydro shop or online store.
At a hydroponics store, you'll find liquid nutrients, specially designed for hydroponics culture. Good ones will come with a grow, bloom, and micro-nutrient solution. Basic ones will have a grow and bloom with the micro-nutrients pre-mixed. Some shops even carry just suspensions of one particular thing, like copper sulfate, for certain plant types. don't use those unless you're a pro.
For a starting plant, you don't use anything but bubbling water for the first couple of weeks while the root system gets developed and can support the plant. After it has established itself and produced more than four sets of true leaves, you can start by using 1/8 of the bottle's suggested strength. Mix in your micro-nutrients first before you put in grow or bloom, and make sure your water is set to a decent pH first before putting anything into the water. For hydroponics, 5.8-6.0 is good pH for beginners.
After a week or so of 1/8 strength, if nothing bad is happening, try upping it to 1/6 or 1/4 strength. After a week, if it has tolerated it and grown nicely, bump to 1/3 or 1/2. Let that cruise at that strength for a week or longer if you're getting the desired rate of growth, then when you're ready, bump it to full strength. Keep your pH checked four or five times daily, and if they deviate, use some pH up or down (you can find this at a pool supply store) or natural sources like baking soda and vinegar to keep it in check. And remember, use grow for vegging, and bloom for flowering. When you're about two weeks from harvest, start using regular water to flush out anything that the plant has not used and has stored up.
Now, for germinating your seed. Put your seed inside of a moist and folded (but not too moist,) paper towel. Put it inside of a plastic bag that you can seal up, and set it in a warm place with little light for a few days. Sometimes they germinate in a day, sometimes they take longer. When the roots are about a quarter of an inch out of the seed, get a rockwool cube, about 2"x2"x2", and poke a hole in it just a tiny bit larger than the seed, about half an inch down. Set the little seedling root first into it and get the rockwool cube moist, then set the rockwool cube down into the hydroton. Make sure the reservoir level is just a little bit above the bottom of the rockwool cube so it gets bubbles.
That pretty much sums up a quick go-over for starting cannabis in hydroponics. a little out of order but if you read it and pay attention this should get you through your grow without much trouble. Just remember to keep that air pump in the bucket running 24/7, and make sure you're pumping a good amount of air through the airstone.
Oh, and as your plant gets larger, you can drop the reservoir level down and let the top roots have some air exposure, and let the rockwool cube dry out. This will help prevent fungus growth on the stem.
