How to set up an apple account on iphone?

I have my mums iphone 4s i got for my birthday and the apple account its connected to is hers. How do i set up my account (yes i already have an account) on the phone? Preferably using the itunes app or computer

Why isn't my iphone turning on?

So it's been a couple weeks since I've charged my Iphone 3S, because we were waiting for a piece to come in since I'd cracked it. Well, today we got the piece and when I went to plug in my phone, that obvious screen comes up that says I need to plug it in to a power source. So I did. And a few minutes later the sliver apple screen came up, and then a loading screen. Then it went back to the screen that tells me to plug it in again. And it's done that several times consecutively. I'm only hoping that since it's been several weeks since I've charged it that it's taking a little while to come back on. But there's also something telling me that's not the case, and when I ruined my screen and digitizer and LCD screen, it ruined something in the motherboard. Please tell me what's up with my phone because I'm really scared.

Iphone Damage? I just dropped my iPhone?

I just dropped my iPhone and I'm worried I damaged it. I have a casemate case on it and I just dropped it on the wood floor. I don't see any damage, there are no cracks or visible damage, and the screen still works fine. But I'm still worried. Is there anything I should check or any damage I might have? I'm kinda freaking out.

Ps. If you know any, please paste a link of the most protective case you know

How to change my iPhone 5 to white?

Okay. So I purchased the black iPhone 5 a few months back, but I find the black to easily scratch and chip, whereas on the white model it doesn't scratch as much. Something to do with the black aluminum to be anodized. Anyway, I'm obviously not going to take it back to the Apple store because that's a waste of a phone. I just want to know if I can take it anyway to switch the casing to white.
Any help would be greatly appreciated!