A Crotchet (Quarter Note), pictured above, is a note that lasts for 1 beat. Crotchets are a solid circular note head (sometimes referred to as a 'blob') with a vertical Stem. A Crotchet written as a cymbal has an 'x' instead of the 'blob'. It is where the note head is positioned on the stave that tells us which part of the kit is played. So if the note head is in the very bottom gap, it will mean 'play a kick drum'.
When counting Crotchets, a number is given to each note. In a bar of 4/4 we can fit 4 crotchets, so we'll just count '1 2 3 4', as shown in the image below.
With sticking there is no set pattern to use. Depending on the tempo they can be played either all on the right hand or alternating 'R L R L'. In the example below they are all played on the right hand.
The example below shows a bar of music made up entirely of Crotchets. Notice that counting is given underneath the bar.
The Stem of a Crotchet may be positioned coming up from the note head or coming down depending on it's vertical position in the stave. When it goes up, it will be on the right of the note head. When it goes down it will be on the left. The image below shows a crotchet with the stem pointing down.