Easiest way to remove it is to buy a scraper for the glass, a gravel vac and rinse your plants in tap water as the algae in question (diatoms) is very easy to remove as far as algae go0es. A brown algae bloom is very common in new tanks and if nothing else shows that the nitrate cycle is working.
How long has then tank beet running for?
So you know the Nitrate reading of the tank? (Very important)
How much light do you have on the tank and for how long a day?