Infantry

O*NET lists no separate tasks for this occupation. It is one of the catch-all groups that gathers jobs not listed on their own, so the record describes it as a whole:

Operate weapons and equipment in ground combat operations. Duties include operating and maintaining weapons, such as rifles, machine guns, mortars, and hand grenades; locating, constructing, and camouflaging infantry positions and equipment; evaluating terrain and recording topographical information; operating and maintaining field communications equipment; assessing need for and directing supporting fire; placing explosives and performing minesweeping activities on land; and participating in basic reconnaissance operations.

The other jobs in Military, below, each list the tasks they are made of.