By reading your questions and I am seeing that you have the right concept but you have to remember that Co2 is a food source for plants the is the main source of food for plants. All the no2, potassium, phos, and micro nutrients are basically a growth product for the plant. Mostly all plants in take Co2 and turn it into oxygen. Humans to the opposite so do fish shrimp mammal well you get my point. Co2 is took into the plant to reproduce more leaves more leaves more co2 is took in.
Now lighting is another big key to to making a plant grow no light plant don't wake up to eat or drink. Causing it to die. It seems you have a great light gonna be enough for your 5 gallon. Remember 2-3 watts per gallon. That's the guide.
Now here is how you dry start moisten your soil. Plant your hc and add real little water to the soil so your don't have worry about watering your plants. Spray your glass and setup a co2 kit. Puncture a hole into the Saran Wrap and insert your co2 line. Set your co2 system to turn on 8 hrs when you lights go on. And boom watch your plants grow. I could be a little more detailed but that's the best I could do