A F Major chord contains the notes F, C, A. It is built from the major formula 1 - 3 - 5, with F as the root.
Why is F major so hard for beginners?
Because the standard voicing is a barre chord: the index finger must press all six strings flat at the 1st fret while the other fingers form a shape above it. It demands hand strength and precise placement that take time to build, which is why it usually comes after the open chords.