YOU'RE PLAYING: Battlegrounds Game.
Let's start with the basic controls :
M: show map
Click (on a soldier): show stats
Shift + click : select/deselect unit
Control * click : send units there
Control t space + click : flee there
Click and drag : select multiple units
From the stats window you can see if your units need to be healed.
In the top bar, you can see the three following sections plus a pause button :
Units selected : shows the units selected out of the total units
Gold : shows your current amount of money
Current quest: shows the number of the quest you are in
Pause : pauses the game and lets you access your inventory
To use an item, you must pause the game and select it from the inventory by clicking on it. Then, press the use button to resume play and use the selected item.
For more info check the in-game manual