You can hear each sound by clicking on his IPA transcription.
Voiceless dental or alveolar lateral fricative. For the dental, the tongue tip makes contact with the inside of the upper teeth; for the alveolar, the tongue tip rests on the alveolar ridge. The tongue is strongly flexed and the air is forced through a narrow oval cavity, producing a hushing sound (see figure 3.26 below).
Voiced dental or alveolar lateral fricative. Same as above, but with vibration of the vocal cords.
This section contains the non-fricative laterals (or liquids, which are rather spirant-like in character.
No distinction is made here between voiceless and voiced variants (it is very rare to for a language to distinguish laterals according to voice).
Dental or alveolar non-fricative lateral. For the dental, the tongue tip makes contact with the inside of the upper teeth; for the alveolar, the tongue tip rests on the alveolar ridge. The air flows over the sides of the tongue (see figure 3.26 again, reproduced below).
Retroflex non-fricative lateral. The tip of the tongue curves up and back and its underside makes contact with the roof of the mouth. The sides of the tongue are lowered to allow the passage of air (see figure 3.27 below).
Palatal non-fricative lateral. The front part of the tongue is pressed against the hard palate. The tongue is arched to allow the passage of air (see figure 3.28 below).