Field training exercises are usually practice "mini-battles" which provide fairly realistic scenarios and situations based on actual situations a unit might face if deployed.
The exercise is usually carefully planned out by field grade or general officers, usually without disclosing plans or other information to company-grade officers.
This makes the situation more unpredictable and realistic since company-grade officers make the majority of quick and immediate decisions on the battlefield.
Nearly every possibility is considered during planning, and often the scenarios can be more difficult or more far-fetched than actual battles, thus sharpening the skills of those participating to a level which will surpass that of the enemy.
In the Army and often in other branches, the last few days of basic training are used to conduct a field training exercise where recruits can practice the skills they have learned over the past several weeks of training.
These exercises generally consist of the entire unit deploying to the location by parachute, followed by multi-day engagements with the "enemy".
The United States Air Force conducts Operation Red Flag four to six times a year.
This is a multifaceted field training exercise consisting of various things such as air-to-air and air-to-ground engagements, mid-air refueling, reconnaissance, close air support, airlift, rescue operations, and special forces operations.