rat
Firstly remember KISS......keep it simple
Fishkeeping compared to your 30 odd years ago has changed a lot and no doubt appears complicated and techie.
But it really doesn't need to be complicated and can be low tech very successfully
I agree with all that's been said so far
The usual temp range for most community fish is 24 to 27. I keep ours set at 26. Indeed that is changable during the summer. When it gets very hot the temp can and likely will reach 30. Even a bit higher. Some things you can do to reduce the temp when this happens is to put some small bottles of frozen water in the tank. Direct a fan at the tank glass. Leave the top open. Turn the lights off. Cool the room temp with open doors fans etc. Close the curtains. Anything you would normally do to cool the room down for yourself really
Part of the treatment for whitespot includes raising the temp to 30.
Don't worry about CO2 at this stage. Yes all plants need it but lots of real plants do fine without added CO2 and when starting out the key is to have lots of fast growing plants that require simple care
Carbon is not necessary. It is useful for removing last traces of medication, but will also remove other things from the water including added plant fertilisers. When it is used it must be changed every few weeks as it will leach nasties back into the water.Some people us it to 'polish' the water and keep it clear, but filter wool/floss does the same thing very effectively with no adverse effects
LOL Dave plastic plants are the work of the devil
......totally my thoughts but we will get told off by my stingray etc al LOL
Not only do real plants look good (we hope!), they contribute towards the condition of the water ie take up excess nutrients like nitrAte and ammonia/ammonium. Provide hiding places for fish etc
But as said, it is possible to have a nice planted set up without the addition of CO2 and high lighting.
To be honest, I'd concentrate more on the fact that you have added fish to an uncycled tank. You'll need to keep a check on the levels of ammonia and nitrIte as both are toxic to fish and can kill them. Both need to be nil so you'll need to do regular small water changes to keep the levels down. The very best way to cycle a tank is to do it with no fish. Have a read at the fishless cycling guide at the top of the tropical setup section.
Hope I haven't sent you to the valium bottle again LOL
Just keep asking for advice when you aren't sure and we'll try to help you all we can
Good luck 