How can one respond to the question from disbelievers: "Who created Allah?" and "How was Allah present from the beginning?" when they are told that Allah created everything?

This question is invalid and contradictory. If we assume the existence of a creator for Allah, the matter would regress infinitely, which is rationally impossible. As for the religious perspective, the Prophet, peace and blessings be upon him, informed us that the source of this question is Satan, and its remedy is for the Muslim to cease the obsessive whispering, and to say: "I believe in Allah and His messengers," and to seek refuge in Allah from Satan. It has been reported that Allah the Exalted is the First, before whom there was nothing, and that He existed when nothing else existed.