This is a brief and simple explanation.
Anyone who professes to be a Muslim is a Muslim. However practicing Muslims observe prescribed rules and actions derived from the Quran and the Sunnah.. These fall into two categories. do and don’t or to stay away from.
Do category. In this category are namaz, fasting, zakat and all other obligatory duties. Also be fair, just and honest in all actions and do good deeds.
do not category. Refrain from envy, greed, malice, resentment, hate and anger, inflated ego, lust, backbiting(gheebat) and stinginess. Also to stay away from gambling, dishonesty in any action, eating pork, consuming alcohol, drugs or any substance that blurs judgement or is harmful to your body.
One must follow the commandments in both categories. Neglect of one negates the other. Therefore, observe all obligatory duties and do good deeds. Strive to remove from your heart hate, envy, greed, malice and other toxic trash listed above and replace them with compassion, forgiveness, truth, generosity, justice, humility, contentment, Zikr (remembrance of Alllah) and other virtues. The goal is to reach a level that brings tranquility, contentment and inner peace which is a great reward but Allah rewards us again in the hereafter. All worldly things stay in this world when we depart, We cane to this world with nothing and leave it with nothing, only our deeds and actions go with us.