A bar is simply a collection of consecutive notes in a bit of music. Dividing the music into bars helps you to keep time by counting beats on your head or under your breath. Bar lines vertical lines mark the start and the top of the bar. Time signatures have a top and a bottom part: the end determines the number of beats and the base determines the kind of beat. The time signature is written once after the clef at the start of a bit of music unless it adjustments. The way the beats are grouped also is dependent upon the time signature, but this turns into more obvious as you build up experience of reading music. The tempo tells you how quickly the music may be played. Usually, tempo is expressed in beats per minute bpm for a specific beat type. This means 50 crochet beats in a minute. To allow you to play at the correct tempo, you could use a metronome. These can be either analogue or digital however the function is a similar: it ticks or bleeps on each beat at the set tempo.