Slides are the same as pedal moves except they use the bar to change to pitch instead of the pedals. Strike a note and raise or lower the pitch with the bar. These are harder to control than pedal moves, but you can move as far as you want from the origin note.
Now try exercise 13. This is similar to exercise 5 but this time don't block between the notes, let each one ring out until you strike the next one. You want the bar to slide in one fluid motion from fret 3 to fret 7 and back. Pick the string as the bar moves over each fret. This is kind of like a glissando effect on a normal guitar. Keep your timing with a metronome.
Here's another slide exercise. This one is to improve wide bar movement accuracy.