Tactics
We conduct war as a Team
One of the first things you learn in the Forces is that everything is done as a team.
There's a specific safety in this principle. If you ever find yourself alone and separated from your element, the prospects of survival diminish significantly. As such it is imperative that one remain an active member of their combat element. For if one were to be wounded or find themselves in enemy contact, the formation allows for a concentration of martial power - thus the bundle of twigs becomes the fasces.
Types of enemy contact
There are two main forms of enemy contact; "soft", and "hard". Soft contact is when a your element observes or encounters an enemy force - who is oblivious to your existence. Alternatively, hard contact is defined as your element's reaction to receiving enemy small arms fire.
Lesser forms of contact include "sporadic contact" and "audio contact". At some points the enemy may engage you from a considerable distance, hurling volleys that may be essentially inaccurate. If struck by these rounds they will wound and in rare occurrences kill if they strike a lucky blow. This is commonly referred to as "sporadic contact"
Audio contact is more disconcerting for light infantry elements than anything else, and refers to actively hearing a vehicle, though generally uncertain as to what the source actually is. This could be a civilian vehicle driving by, or a suicide bomber, or an enemy IFV/APC. With this being said, one should not dismiss the audio contact as the civilian potential and expect imminent contact with enemy mechanised and/or armoured elements.
Reacting to contact
In day to day life it is easy to become complacent in our movement. How we saunter from room to room or from street to street requires limited awareness on our part. But in a combative environment one's survival hinges on their ability to find hard cover - an obstacle, any obstacle, that would stop an enemy's bullet. So during an operation it is necessary that when you move, you move not only with purpose but with a keen eye for your next bit of cover or concealment.
Ultimately, cover will stop bullets, but concealment might mitigate your enemy's ability to accurately shoot you. As such it is
An example of soft contact: Your fireteam needs to clear a specific segment of a village. Depending on the geography, Your fireteam leader may situate your auto-rifleman as a suppressing base of fire from the treeline or on a nearby hill whilst a second group manoeuvre into the village.