All 22 letters, each with its sound, gematria value, audio and words that start with it. Switch between print, handwriting and the Rashi script used in commentary, then open any letter for the full page.
Most adults read the letters within a week or two of short daily sessions; the alphabet itself is small, and several letters share sounds in modern Hebrew (kaf/kuf, tet/tav, chet/khaf), which shortens the list of sounds you actually need to learn. Reading unvowelled text quickly and confidently takes longer, because it is a fluency skill built by reading, not a fact about the alphabet.
Handwriting is a separate step. Israeli schools teach the cursive forms directly after print, and several letters change shape enough between the two that they are worth learning as their own thing: see the notes on each letter below, or the print-versus-handwriting comparison on the cursive page.