Hi~ Thanks for dropping by~

1) Go to [Mission] and just idle for a few minutes until you have leveled up to level 3 & accumulated 3 TP
(TP i guess stands for Training points)

2) Then press [Return] and go to [Home] add them into your Atk. [PlayerAT]
You should be able to one-shot enemies (level 1 Mission)

3) Thereafter, just keep idling in [Mission (first level)] and when you've gotten your first 100 gold, go to [Shop] and buy the item at the most right, which is the potion icon (xp boost).
(The xp boost item will cost +100 gold everytime you purchase it)

4) Subsequently as you level, just keep adding your TP in wisdom instead.
Why wisdom? cos wisdom gives you +exp gains~
And as you level, your coin gains will increase too~

5) Just rinse and repeat step 3 & step 4 and you'll hit level 40 in no time!

Thanks for your time reading~