Clouds are a Symbol used throughout the Bible~
Study this from beginning to end and learn the meaning of Clouds. It is not just in the context of Acts or Matthew, for the foundation is laid out before that in the Old Testament, many times!
A study of "clouds" and "up" and "ascension" in the Holy Bible https://www.studylight.org/commentary/acts/1-9.html These are selections from major theologians and Biblical scholars who offered commentary on this perplexing prophetic chapter in The Book of Acts included in the New Testament.
THE ASCENSION OF CHRIST AND ITS LESSONS.
IN this passage we have the bare literal statement of the fact of Christ’s ascension. Let us now consider this supernatural fact, the Ascension, and meditate upon its necessity, and even naturalness, when taken in connection with the whole earthly existence of Incarnate God, and then strive to trace the results and blessings to mankind which followed from it in the gift of the new power, the covenanted gift of the Spirit, and in the spread of the universal religion.