Interestingly, the game takes you through a lot of tutorials when you first start it up, but one of the few things it never actually tutorialises is your team size, which is bigger than you might expect.
I spent a bit longer than I'd like to admit with a team of three soldiers on the ground, taking down waves of enemies with tactical uses of abilities. Which is great experience. But also unnecessary.
Your max team size is actually five soldiers, so you should make sure to add five soldiers to your team as soon as possible. You should earn at least two extra soldiers past the tutorial easily from the campaign and objectives.
Each of your soldiers can be upgraded in a number of ways - the most obvious one is training, when you can splash your cash to increase the level of your soldiers.
Next is the gear system - you can collect and equip pieces of gear, and once your character has a full loudout their gear can be upgraded, at which point you'll need a fresh set of gear, as it's used up in the process. This is also a permanent buff to the soldier's abilities, so well worthwhile.
And finally, you have weapon upgrades. As your soldiers enhance you'll be able to spend money on getting them upgraded weapons - the progression system is linear, so just get whatever is newest and you'll have the best loadout.
Objectives and missions
Once you're out of battle and back on the main screen you'll be able to check your objectives in the bottom right, and here's where you'll find the targets you want to meet.
First off are the daily objectives of course, and then the primary objectives which primarily consist of campaign milestones.
And then there are the objectives you haven't unlocked yet, and you can still click these to see exactly what you need to achieve in order to unlock your rewards.
These are incredibly important, and will save your life in dire situations. While in battle you'll have two abilities you can access at any time, and your timing with these should be precise.
The two most useful abilities in the early game is the Airstrike and the Heal abilities, one for attacking enemies, the other for keeping your team healthy so you can earn all the medals on each stage.
In general you should just all-out attack and heal whenever possible, but whenever the enemy numbers are low and your airstrike is free, make sure to check if there's another wave coming before throwing it down on a single weak enemy.
These are basically lootbox chests, and they will contain a big variety of gear, items, and character intel so you can earn more soldiers.
You will get ORBs and items to trade for them fairly regularly, as long as you keep smashing through the campaigns and objectives - or you can trade gold for them.
Gold is a fairly rare currency and has multiple uses, so make sure you have plenty to spend before you splash what you earn on ORBs.