The slide is a technique which involves a finger moving along the string to its new note. The finger maintains pressure on the string, so that a continuous sound is produced, until the desired note is reached.
The hand moves from one note to the next, upwards or downwards on the fretboard.
You can now combine tapping with sliding which will enable you to play more melodically.
The following two exercises use the index finger on the D string for the sliding movement. Play the note E on the G string with your 2nd finger.
The following exercises should be played in different positions.
Make your own exercises by firstly using a slide note followed by a tapped note. Use various intervals.
In the following tapping exercise, walk down the fingerboard starting at the top of the neck. Alternate the first and second finger(s) of the right hand on the G and D strings.