Next section, special combat actions
There's stuff you can do other than move, attack, and use items. I'll list some of them you might find useful below. The full rules on all of this can be found here:
http://www.d20srd.org/indexes/combat.htm
Full Attack: By spending a full round (you move action and your standard action both) you can make multiple attacks if your base attack bonus is over 5. That can't happen till you're level 6 though so it's not so important yet. When you get multiple attacks, your attack bonus is reduced by 5 for each attack. eg: When you have BAB 6, if you spend a full round attacking you get one attack with a BAB of 6 and another with a BAB of 1.
Attack of Opportunity (AOO): A lot of people hat the system for this mechanic, but I think it's fine. Basically, once per round if an enemy in you melee reach drops their guard you can make a free attack against them. Circumstances that provoke attacks of opportunity include
-moving out of a threatened space
-drinking a potion
-casting a spell
-making an unarmed strike (I keep doing this XP)
-many more
There are ways to get around most of these as well. For example, a spellcaster can make a concentration skill check to "cast defensively" and avoid provoking an AOO. Unfortunately, if they fail the check they waste the action (and the spell). So yeah, doing some stuff while you're in melee range is a bad idea.
5 foot step: This is a special form of movement. You can take a 5' step in any round that you don't spend an action to move. It doesn't count against your actions in any way and lets you avoid attacks of opportunity (because it doesn't count as moving).
Withdraw: This is another way to avoid an AOO if you need to move. Basically, if you do nothing but move in a round, the you don't provoke an AOO while moving away from an enemy who was next to you at the start of your turn.
Initiative: Oops I never covered this >.< This is what you do at the start of combat to determine the turn order. Basically, everyone rolls a d20 and adds their dex modifier, highest goes first. Some other things effect initiative (like feats) but most people just use their dexterity.
Special Attacks: You can do stuff like trip you opponent, push them backward, or feint. I'd describe them all here but I'm lazy. You can look
here for a full list. Yes, they're overly complex and a lot of them provoke attacks of opportunity.