Your English is just fine.
Let's look at Kyra, the cleric
Her attack bonus is +1 on the scimitar and -1 on the sling.
On her character sheet, in section G, it shows you how the melee attack bonus is calculated. Just under that it shows you how the ranged attack bonus is calculated.
If it's not in that step-by-step calculation, it isn't included in the bonus.
Weapon proficiencies generally make it possible to use a weapon without penalties. Her weapon proficiencies are shown in section E. If you aren't proficient, you have penalties. If you are not proficient with a scimitar and try to use one, then your attack bonus suffers a -4 penalty.
As you can see on page 42, Kyra has Martial Weapon proficiency, because that is part of being a cleric. There you can see the penalty (-4) for not having that.
Clerics of Sarenrae are proficient with scimitars because that is their goddess's Holy Weapon, See page 18 of the Hero's Handbook.
Kyra's feats are listed in section I. She doesn't have the Weapon Focus feat, so that isn't relevant to her attack bonus.
Ok, on Ezren's sheet, it says, under Quarterstaff (Section G) that his attack bonus with that weapon is +1. (AB +0 Str +1 = +1)
Where are you seeing an attack bonus of +2?
Valeros. Again, on his pregen sheet, his attack bonus with his longsword is +4. The calculation is shown at the beginning of Section G, and there is no difference between his attack bonus calculation (AB +1, Str +3 = +4)and the attack bonus shown under the weapon.
Where is the +5 coming from?
Merisiel. Her normal attack bonus is +1 (AB +0 Str +1 = +1). She has the feat Weapon Finesse, which allows her to substitute her Dex bonus for her Str bonus when using the rapier (Weapon Finesse: When making a melee attack with a light weapon or rapier, you may use your DEX Mod instead of your STR Mod on the attack roll.)
On which page?
On the pregen sheets from the Beginner Box, I'm not seeing the numbers (+5)that you're seeing
Huh. My sheet has a four there.
Let me look around and see if there was an errata or whether something got changed.
Ok, here's a Beginner Box errata thread
Valeros Errata
From that it looks like his attack bonus when using Power Attack should be +4, but otherwise +5
I'm working from the PDFs. I'll take a look later this week at my print copy to see if it matches yours
Sure, no hurry, but I can rest knowing that my doubts were well founded. Anyway, as detalied before, I think there might be errors on Ezren and Meriel weapons too...
Read through that whole thread. There are a number of errors that are explained there.
And keep asking questions. People can help you figure out what the correct answer is, in spite of errors
Ok, I finally got hold of my physical Beginner Box.
As you say, the sheets in there have errors. Mine have the same ones yours do
I'd suggest you use the thread I linked to to see what errors have already been found and discussed. If you have access to the BB PDFs here, download a new one. The PDFs are updated and error corrected.
If you think you've discovered different errors, start a new thread and people will help you calculate the correct numbers