Dragon Knight is a very basic adventure RPG of the "grinding" variation, meaning you have to slay a lot of monsters to get the necessary gold to buy new stuff.
The game is quite simple:
you start in midworld
in each town you find an inn where you can rest and restore your health for a price, as well as 2 stores where you can buy maps to other cities (for fast travelling), weapons, armour and shield.
by exploring the world, you encounter at random some monsters (on average 1 for every 10 steps you make). Some monsters drop useful items you can equip.
for each slain monster you get extra experience (XP). Once you have enough XP, you gain a level, more HP and XP