This map shows how to get to the School from Maadi and Heliopolis. 

From Heliopolis:  Unless you know your way really well through Nasr City, come out onto Suez Road past the city limits police station.  Pass Jeep factory on your left take slip road on right for Maadi and Helwan.  PASS turnoff for Kattameya Golf club and U-turn at next break in road.  Then turn right towards Kattameya Golf & Country Club and look for BLUE signs saying New Cairo British International School

From Maadi:  get onto autostrade passing McDonalds on your left.  Go under bridge onto slip road.  Take first right (where they are constructing  new flyover) and go straight on.  Pass turn off for Ein Suhkna, pass Shell garage and follow signs for Kattameya Golf & Country Club (on your right).  Then look for BLUE signs saying New Cairo British International School.