The Minor 7 flat 5 (m7b5) is easy to understand because the name itself spells out the chord. These chords are also sometimes called half diminished chords. Shown below is an arpeggio of a Cm7b5 chord. Once you are comfortable with it, learn it from memory in all keys.
Minor 7 flat 5 chords are most commonly found as a 2 chord in minor keys. The following example demonstrates a typical use of this chord type.