These are very impressive, rising as they do straight out of the plains of the South Turkana lake basin.
The Cherangany group, south of the Marich Pass, includes Koh, Kaok and Sondhang. The latter is most accessible from Ortum; the other two from Lomut or the Tamkal Valley.
The Sekerr group, north of the Marich Pass, includes Mtelo and Chaichai.
Being much higher, they should be ascended from a “base camp” such as Mtelo View Campsite.
The Tiati group consists of Tiati (or Tiatich) itself and its outlier, Cheptumat.
None of these mountains require climbing skills; all that is needed is strong hiking ability and endurance. But, never forget the climatic conditions ---- in the hot, dry months heat-stroke and / or dehydration are always possible if precautions are not taken.