Can I Install AoE II DE on Two Computers?

I am wanting to purchase AoE II DE to be able to play with my son (nostalgia and shared memories!), and to do so, will need to install on two computers so we can play against each other. If I purchase one copy of the game, am I allowed to install it on two different computers in our home so we can play each other, or does it require two separate purchases?

Yes, it will require two purchases with two different accounts (on Steam or MS Store) in order for two people to play at the same time.