You must begin with the first

“It is not wisdom that we should have all knowledge at once presented before us; but that we should have a little at a time; then we can comprehend it.

“When you climb up a ladder, you must begin at the bottom, and ascend step by step, until you arrive at the top; and so it is with the principles of the gospel—you must begin with the first, and go on until you learn all the principles of exaltation” (Teachings of Presidents of the Church: Joseph Smith [2007], Joseph Smith)