Our basic infantry squad runs 1 support, 1 medic, 1 assault, 1 anti tank.
4 man squads are more practical. With 6 people, you are a big target. You also have 2 unneeded men. You only need 4 at the most. Most vehicles cannot carry 6 people. You don't want one guy walking. If a medic dies, have someone pick up the kit.
Medic- Heals/revives, able to kill infantry
Support- Resupplys team, provides cover fire
Assault- squad leader, profficient in killing infantry, smoke cover/ flash bangs
AT- Able to engage armor
This provides the ability to take on most combat situations.
Also, we have 2 specialty squads. An armor squad and a Sniper squad.
4 people make up the armor squad. 2 Supports, 2 engineers. That way, the convoy is self susstained. They can repair and resupply each other.
The sniper squad consists of two snipers. A spotter and a shooter. Both can hit targets at long range and can spot targets for friendlies.