How do I lock my iDevice? What about turning it on or off? Resetting?
All modern iDevice devices have several buttons on them. The ones we will be concerned with are the home button, the round, flat button on the front of the device below the screen, and the power button, a rectangular button found on the side of the device.
To lock or unlock the iDevice, simply press the power button. If the iDevice is on and this button is pressed, it will lock. If it is locked when this button is pressed, the "lock screen" will appear. The time and date will be displayed, and at the bottom of the screen will be a control labeled "slide to unlock". Double tapping this will unlock the device. If you have set a passcode, you will now have to enter it. Otherwise, the iDevice will unlock and be ready to use. Note that the home button can also be used to unlock the iDevice, but not to lock it.
To completely shut off the iDevice, press and hold the power button. After a few seconds, a screen will appear with a "slide to power off" control at the top of the screen. Double tap this to turn off the iDevice. Alternatively, just keep holding the power button until the device shuts off, about ten seconds. The power button is also used to turn the iDevice on; press and hold for about a second (in my experience at least - you may be able to simply hit the power button and have it work).
Many mobile devices have a "reset" button on them which is used to recover from a freeze or abnormal behavior. The iDevice line does not include this. If the iDevice freezes, pressing and holding the power button until it turns off, then turning it on, will normally do the trick. This is as close to a reset as I know how to perform.
How do I manage wifi, such as joining networks or turning wifi on and off?
Go to Settings, then Wifi. Here you will find a list of all networks in range. Simply double tap one to connect to it. If the selected network requires a password, you will be prompted to enter it before the connection can start. You will only have to enter the password once.
You have a few other options in the Wifi settings area. First, you can turn on or off wifi by double tapping the "wifi" switch button, which will act as a toggle. You can double tap the "more information" button that appears after each network to get more information about the network, or to tell the iDevice to "forget" the network. Forgetting will remove any information you had entered about that network, such as a password. Finally, you can choose whether known networks are joined automatically or not (the default is "yes", which means that a network the iDevice recognizes will be joined as soon as it is picked up instead of you having to join it manually).
Help! VoiceOver has stopped speaking and I can no longer use my phone!
Don't panic, You have most likely just muted speech. If you have set up tripple-click home, just use it to turn off VO, then turn it back on. Even if it is muted, VoiceOver will always start with speech on. You can also try tapping three fingers on the screen twice (the "three finger double tap") to toggle speech on and off. If that fails, turn off the iDevice completely and turn it back on again.
Still not working? Connect the iDevice to a computer and bring up iTunes. Select the "summary" tab (radio button on Windows), tab over to universal access, and check the enable VoiceOver box. Sync with the iDevice and VO should be on again.