Lighting - levels of lighting is worked out in wats per gallon (WPG) it is the toal wattage of the lights, dividedd by the toal US gallond of your tank, in your case 30w/ 30g = 1WPG
1WPG is the minimum light you can have that is needed to grow plants succesfully like mosses, java ferns, anubias, crypts, hygrophilia, vallis...
1-2WPG low light,
2-3WPG medium - high light
3WPG+ High
the colour spectrum is measured in kelvins (K) plants photosynthesize in with a K in between 5500k - 11 000k, the spectrum doesn't matter to much, as long as you have enough light then dont worry to much.
CO2 - Carbon dioxide (co2) is where plants use the carbon © for starch which is used for energy, if the plants take in enough (along with other factors), they will start pearling and give off oxygen (O2). CO2 is only needed when you have 2WPG+ because the high light drives plant to use more ferts & co2 so if you dont have co2, then there is no point in having high light, you will just get algae, you can use co2 under 2WPG but there is no real need.
co2 can be measured by measuring your kh then refering to a co2 table (in my sig) or you can use a drop checker for a constant more accurate result.
the water will contain a small amount of co2, usually about 6ppm (parts per million) but it isnt enough for plants.
0-25ppm low BLUE
25 - 35ppm GREEN
35ppm+ high YELLOW
fertilisation - there are various types of fertilisers and methods, you can use an off the shelf product which will be ok for what you need at the moment, then you can get better ones like TPN+ (tropica plant nutrition+) it contains NPK (nitrate, phosphate, pottasium) then there is EI dosing which is used in hi tec set ups (high light, co2) i wont go into EI as i dont think you will e needing it but ask if you want to know or there is the pinned thread.
To sum it up -
you have low lighting which will grow mosses, java ferns, anubias, crypts, hygrophilia, vallis, elodea/ egeria densa, echindouros species
CO2 - not needed for the above plants or your lighting levels
Ferts - an off the shelf product will suffice for your levels of equipment, root tabs can be dosed near the plants roots to help if necassary
Hope this helps as a basic starter guide
Thanks, Aaron