Welcome to the Paizo forum! Lilith should be along some time with cookies...
As a starter, I'd recommend reading the following:
Getting Started (this one is particularly handy since it defines a lot of basic terms for the game)
and
the How Combat Works section in Combat
This will give you the overview of combat to help frame things up.
Base Attack Bonus, or BAB, is a number assigned to every character/creature and is based on class levels (each class has a chart listing BAB) and/or Hit Dice (i.e. how many dice you roll for the creature's hit points).
You might try using a character generator to select a few character options and see how things work together (I've got a free one linked in my profile, or you can download fancier ones as demos, such as Hero Lab).
After you give it a whirl, keep asking questions. The folks around here are very nice and helpful at getting things started.
When making a melee attack: sword, fist, some hand-to-hand weapon, you apply your BAB + Strength modifier + any enhancement bonus of the weapon + Weapon Focus feat (if you have it).
When making a ranged attack - bow or a thrown weapon for example - you apply the same formula except adding Dexterity modifier instead of Strength.
On top of that add any circumstantial modifiers: cover; invisible; flanked etc. You'll find all this in the combat section of the Core Rulebook - attacking p.182/ circumstantial mods p.195
hope that helps!
When making a melee attack: sword, fist, some hand-to-hand weapon, you apply your BAB + Strength modifier + any enhancement bonus of the weapon + Weapon Focus feat (if you have it).
When making a ranged attack - bow or a thrown weapon for example - you apply the same formula except adding Dexterity modifier instead of Strength.
On top of that add any circumstantial modifiers: cover; invisible; flanked etc. You'll find all this in the combat section of the Core Rulebook - attacking p.182/ circumstantial mods p.195
hope that helps!
LoL, Tanis, did you know all that on your first day you ever played?
To the OP:
Question: How do you eat an elephant?
Answer: One bite at a time!
The rules to this game are your elephant; there's a lot here to digest (pun intended, of course). So take it one bite at a time.
1. Make a character. Yes, you will make mistakes but this is just for practice - you're supposed to make mistakes when you practice (unless you're practicing medicine...
2. Find a monster, like a goblin, or make a second character.
3. Go to the Combat section and start right at the beginning.
4. Roll initiative like it says.
5. Whoever goes first, look at all the actions. Review action types (standard, move, full-round, free, etc.). Pick the action you want to do, then find the combat rule that governs that action - if you want to swing your sword, look up attack, it will explain everything.
6. Now take the other guy's turn. For fun, pick a different action.
Repeat as often as you need to, one bite of the elephant at a time.
Really, that sounds like I'm being simplistic, but if you actually do this, you'll be amazed at how fast most of this clicks into place.
For example, when you go to make your first attack, you will need to read the "Attack Roll" section. It says that your attack roll with a melee weapon is Base Attack Bonus + Strength modifier + Size modifier. That's it. So use that. But what do you need to hit? For that, you need to look up Armor Class, which says your AC is 10 + armor bonus + shield bonus + Dexterity modifier + other modifiers and then it goes on to give examples of those other modifiers. You might have to look those up to fully understand them. And so on.
After you've done that just a couple times, you'll have the basics. Then you're ready to move on to the next step. Ask yourself what happens if you're fighting in the dark? What happens if your opponent is invisible? What happens if he's 20' tall? Or 2' tall? All this stuff is in the Combat section, along with tons more. Take them one bite at a time.
Best part is, you don't have to know it all right now. Your players are new too, right? So just get them all together and roll up some characters and start with a published adventure from Paizo. No, I'm not trying to sell their stuff, but making an adventure on your own is a lot of work and you need some experience to get it right, so buy one for starters to see how it's done, and who knows Pathfinder better than Paizo?
As you play, more and more questions will come up, and you'll usually find those answers in the rulebook, and as you do, you'll be digesting more bites of that big elephant.
If the book doesn't answer you questions that arise in your game, just make something up that's fun at the time and keep playing. When everyone goes home, come online here and ask about the things that puzzled you during play. Mmmmm, more digestion.
Pretty soon that elephant will be gone.