I have no idea what I'm doing

[rpeg]

I enter a battle. I lose some units. Sometimes I win the battle. I get some money and then I buy more units. REPEAT. Unfortunately after a while I'm out of easy enemies to battle and out of money to buy enough units to actually compete.

I don't understand this game.

It seems that I should have spent more money in the beginning to purchase enough of the units to compete more aggressively in battles and win more money! However I did not know that and now I have no idea what to do. I can hardly afford to purchase any units at all and I all the enemies around are too difficult to battle with the limited units I have.

Why? Am I supposed to completely back track and start over?