Hi Chris, welcome to the forum
In terms of getting a carpet going which plants were you looking at doing? If you're not sure of names were you thinking of a grass type plant or one of the small leaved plants like Monte Carlo?
Carpets can be quite hard to get going without Co2 but it is possible. You really want a nutrient rich substrate - I've started using Wio Eonian as its a long term substrate and you don't get the ammonia spike at the beginning. But I'd recommend capping it with a sand as its quite a coarse texture especially for fish. Having a good liquid fertiliser will also help, I use Tropica Nutrition (the brown one without nitrates).
It's worth mentioning though that carpets can limit the species of fish you keep so make sure your fish are ok without access to sand for example. Cory cats are a good example as they like to dig in the sand and filter it for food so will disturb your plants a bit in a way that means they won't fully cover the substrate.
Another option if you want to have that aquascaped look is to have a sand substrate at the front and plant a few foreground plants without the full carpet - I think this looks more natural to be honest. You can always mix in a hand full of gravel around bigger rocks to make it look more natural too.
Wills