How to use the half pattern
These patterns can be considered a 2/4 pattern or it can be considered a pattern that is worth half a measure in 4/4. If you play a half pattern twice in a row you would have a full measure of 4/4. So why would you use this?
Some songs have chord changes that happen exactly half way through the measure (on beat three). So in those measures that have chord changes like that, you could use these patterns. A common way I use these is for the parts of the song that stay on a chord for a full measure I use patterns that have no beat 3. Then on the measures that require a change on beat 3 I might use a couple of these half patterns.
In the future I will have some lessons where I demonstrate this for you.