This does not need to be removed. Dirty dirt means the uneaten food and the bodies of fish that may have died. These kinds of things need to be removed. Beginners will have to start with plain tap water. Letting the water stand until it comes to room temperature will get rid of any chlorine that may have been added to the water to purify it.
Chlorine is very harmful to fish.
Your fish may be added as soon as the water in the tank does come to room temperature. At first the water may look a little cloudy, but this is normal for a new tank. If you feed your fish very sparingly for the first two weeks, this should clear up and remain clear. Plants are important in an aquarium, but not as important as many people would have you to believe. Plants do not provide the fish will all the oxygen that they need.