An active team of soldier will ride the UFO to the battle map, with the sole exception of AL:Home Base Under Attack (Event).
Arrives at the battle map, the team start out at the entry zone, accessible to the UFO's trunk and can change equipments here. Entry zone is different each time and unknown which type of elements affect where it is. Team also start out at Walk stance and walk pose, despite trainings.
Sometimes the mission require team return to entry zone to complete, despite killing every hostiles and bring mission items on hand. Example is First Moon Mission
Environmental hazard will break the suits first if it's beyond suit's rated capability. After that, hazard will lower team member's HP at different speed depend on how high it is. This kind of loss HP doesnt show itself as different from wounds, but can be healed more easily in-map than wounds.
Maps have several type of base terrrain which change along planet's terraformation (causing plants to appear and block route) as well as the number of facilities in that area. A fully built up area will have map with many extra structures that create new terrain advantages or disadvantages. In fact, a map in a virgin area at starting stage will look very different from one in terraformation 50% for example and fully built up. This has strong bearing on tactical combat.
Sometimes mission is impossible to complete and you simply have to abort by clicking on Abort button. Standing on entry zone to abort is better than elsewhere, but Abort has a dangerous result that people simply reload from before taking it, than abort. The sole exception is first time attack Zephyr's Fortress of the Beastmen where you just dont have to take this mission. Until late game event happen that permit successful assault here.
Complete or fail the mission will open final tally screen where you can see xp gain, HP healed or loss, enemies killed, damages heal or lose etc... Damage dealt out gain XP, along will killed hostiles. Scientist can gain xp in mission rated for science xp, and gain xp for amount of healing they did in map. Technicians can gain xp in mission rated for tech xp and gain xp for suit fixing, mine dismantling but the amount is not easily understood yet.
A successful mission with all enemies' killed allow looting phase to happen. You can see loot items and corpses on the ground and gather them all to UFO's trunk. Or into your team member's personal inventory. Sole exception is two-stage mission related to underground maze, the so-called robot excavation missions, when the 1st stage loots often get ignored in final looting phase.