Unlock the Mantis saddle and taming tools
Craft Bug Repellent
Craft a Ghillie Armor set
Gather Deathworm Horns or Woolly Rhino Horns
Find a wild Mantis
Use Bug Repellent before approaching
Wear Ghillie Armor
Equip the horn in the last hotbar slot
Crouch and approach slowly from behind
Feed the horn when the prompt appears
Repeat feeding until taming is complete
Keep distance from other aggressive creatures during taming