A level-appropriate encounter for a starting character, Gear Up teaches you about upgrading your equipment. Start by linking minds with Senu to get an overview of the area.
What you're looking for are little circles containing the 'Soft Leather' icon. There should be a number of them by the oasis just outside of town. Tag them with the left mouse button, then return to biped mode.
Hunting the ibex is much like you'd expect- don't get so close that you spook them, go for the headshot, and be aware that shooting one will cause nearby beasts to scatter. Each time you down one, approach and loot the carcass for your skins. When you have five (and a single carcass may yield more than one unit of skin), go to your Gear screen to upgrade your breastplate.
Finishing this bit of craft completes the mission.