be aware that some fish eat plants naturally, some plants they may not if the plant tastes bad to them for whatever reason. It is a natural, normal, and healthy thing for even well fed fish to occasionally nibble. Research your wet pets to learn if they are avid plant eaters, or if they are known for uprooting plants with their behavior.
too much light grows algae without ferts and co2.
ferts are not necessary without light and co2.
Adding Co2 will really only benefit if the lighting and ferts are decent. A low tech tank (low to medium lighting) can get enough co2 if adequate water surface agitation exists to help increase co2 going into water from normal air. Just remember that surface agitation is bad when injecting co2 gas directly, as it will have the opposite effect.
Here's my opinion of a good game plan if you must do it step by step.
First step is to read the first sentence in my signature. lolz.
Actual "dirt" sucks as a substrate imo, but if you get fancy planted aquarium substrate, like Seachem Flourite , then that's a good place to start.
This will involve a full tank overhaul obviously, so treat it like a brand new setup. Give the water chemistry and filter system time to stabilize before adding too many fish! However, you can fill it with as many "easy" and "low light" plants as you want. Many of which will die back a little or even wilt, but after a month or two they are used to thier new home and bounce back.
Begin dosing a "micro" nutrient or "trace" nutrient like Seachem Flourish as per directions on bottle.
Upgrade your lighting to 3+ watts per gallon, but only run the lights for 5-6 hours per day until you get a co2 system. Otherwise algae grows out of hand.
Get a co2 system, begin dosing "macro" nutrients : nitrate, potassium, phosphate, and increase photo period to 6-8 hours per day.
Add fancier, higher light, more demanding, or advanced plants.
