How can one pray Dhuhr and Asr at school in Europe without knowing the Qiblah, and is it permissible to pray a short time before the Adhan based on a prayer timing program?

The time for Dhuhr prayer begins when the sun passes its meridian (zawwal). If it is difficult to ascertain the exact beginning of the time, one can follow a trustworthy muezzin or use accurate computer programs. It is not permissible to pray before its time, and the obligatory prayer must be performed within its prescribed time, while observing its conditions and pillars. The Qibla can be determined using a compass. Prayer is the greatest pillar of Islam, and one must be diligent in performing it as Allah has commanded.