There were obviously more humans created than just Adam and Eve, but to simplify things for people, God gave Moses, and later Mohammed, the simple story of one man and his wife - Adam and Eve.
Listing the family-trees, of all the people, would have made Genesis, the Bible and the Koran (Quran) into a library of 10-20 volumes, and they are already so big, that many people allow Satan to intimidate them, into not reading them, because of their size.
Confirmation in the Bible that there were others besides Adam and Eve may be found in Cain's fear that word of his crime would spread, so that others would try to take his life wherever he drifted.
Genesis 4:8-16
4:8 And Cain talked with Abel his brother: and it came to pass, when they were in the field, that Cain (Possessions) rose up against Abel (the breath of Life) his brother, and slew him.
4:9 And the "I AM" said unto Cain, Where [is] Abel thy brother? And he said, I know not: [Am] I my brother's keeper?
4:10 And He said, What hast thou done? the voice of thy brother's blood crieth unto Me from the ground.
4:11 And now [art] thou cursed from the earth, which hath opened her mouth to receive thy brother's blood from thy hand;
4:12 When thou tillest the ground, it shall not henceforth yield unto thee her strength; a fugitive and a vagabond shalt thou be in the earth.
4:13 And Cain said unto the "I AM", My punishment [is] greater than I can bear.
4:14 Behold, thou hast driven me out this day from the face of the earth; and from Thy face shall I be hid; and I shall be a fugitive and a vagabond in the earth; and it shall come to pass, [that] every one that findeth me shall slay me.
4:15 And the "I AM" said unto him, Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And the "I AM" set a mark upon Cain, lest any finding him should kill him.
4:16 And Cain went out from the presence of the "I AM", and dwelt in the land of Nod, on the East of Eden.