Here's where I'll explain the menus and tell you how to increase your character's status when they level up. Lets take a look at the picture below.

This is the Start Menu. The two words in that pic pretty much explain themselves. You'll unlock 2 more menus there when you get so far into the game. I'll tell you what they are in the Secrets section. Now we'll take a look at the in-game menu.

Status displays the characters you have and their stats. When you level up, you can also come here to distribute the 5 extra point you get from leveling up. More on that later.
Deck allows you to add or remove cards from your deck. You're deck is made up of joint cards and it can only have 20. After you've drawn all 20 in battle you don't get to draw anymore, but the battle will continue.
Team lets you choose your team for battle if the situation allows it. After beating the game once, you can use whatever character(s) you want.
List just displays all the cards you have collected. You'll end up playing through the game many times to collect them all without cheating.
Save pretty much explains itself.
Exit will take you back to the map area if you're on the map, but when you're about to start battle, it uh...lets yoo start the battle.

Guess it's time to tell you how to level up and distribute the 5 points to add to one of your stats after you level up. The maximum level is 5. You probably know that leveling up can only be done by fighting. Your stats will increase on its own, but you also gain 5 points to give to one of your stats.
Increasing your HP lets you last longer in battle.
Increasing Strength will increase the damage you do with a damage card or command card.
Increasing you Ki will increase the amount of damage a beam attack will do.
Increasing Speed will increase your accuracy and avoidance. Speed will also determine which character goes first.