No problem at all being a beginner, that is why we the old folks are here, to help them out !
The light seems awfully small, do you have any specifications on that (Watts, Lumens, Kelvin,..)?
You better replace the substrate, this is impossible to clean and it isn't doing anything for the plants. Don't worry it can be done with the fish still in the tank. The best substrate is 2mm to 3mm size (so coarse sand or fine gravel). Dark or black will make the fish more at ease and show their colors best. ±1" max height. The rocks are used for aquascaping, you can use them for decoration, maybe make a couple of mountains of them but you want like 2/3rd to be the right substrate for vacuuming and the plants. After removing the rocks, rinse the substrate very well before putting in, until the water that comes off is clean. Then put it in a plastic cup, lower gently in the tank and slowly pour it out over the bottom. Then put the plants back in and the rocks/pebbles you want for decoration. If you have more questions just ask..
