I see nothing untoward in what's written there. What is it that puzzles you..? The numbers are the fret positions for each string, the oblique lines are the strokes to be played, for the duration indicated by the horizontal bars joining the notes. The 'dot' indicates that the length of the note is to be 50% longer than normal. The 'mf' means quite loud, the 'p' means piano, so softly, the 12/8 is the time signature (rather like 3/4 waltz time, but faster, like jigs and reels...). That's it, really. What have you not encountered before..? ('Bohemian Rhapsody' is not really a 'beginner' piece; it has its complexities...).
Hope this helps, if not clarify your concerns..?