I have an iPad mini cellular. What should my settings be to use wifi when not in a wifi area

Theres only three ways to connect to the internet depending on the iPad you have.

Wifi
4G (If you have a 4G iPad)
Hotspot from your phone. Most phones can share your data and create its own wifi network, sharing it to your iPad.

Are you sure of Wifi password is correct?
if so, 1st; try restarting your ipad by holding down power/sleep button untill it show "Slide to shut down" leave it off for 10 seconds & then re-open it.enter the Wifi -password, sometimes this step works.

2nd solution ; try resetting your iPad network settings, it will not affect your ipad in any thing except it will forget all entered passwords for any wifi you have already connected before. go to General from Setting, choose resett, and inside only reset network setting, shut down ipad & try to connect to the wifi again. Hope this solution work for you. Also you may try shutting down & opening your router again after 10 seconds while off. Good Luck.

You can manage files on your iPad mini with this iTransfer tool. It also helps you add/remove files like books, movies, photos, etc.
Transfer Files among iOS Devices iTunes and PCs with Ease

You should be able to click skip during setup. It will need wifi to be able to access anything else, since it's a tablet and isn't enabled with cellular data.

Leave the password field blank in accounts

If you are using a cellular iPad mini and you are using WiFi turn off WiFi and your mobile network will allow you to send pictures its classed as sending an MMS message if it still won't work you need to get the MMS settings from your network (Vodafone, o2 etc) or if you have a WiFi only iPad then you can't use Imessage to send pictures as it won't work over WiFi but messaging will
I have added a link to give you more help
iOS Troubleshooting Messages

Connect it to your PC via USB cable, then start iTunes.

Plug it into your computer and select factory reset on it in iTunes.

Always a good idea to shut down and then turn back on (hold down both home button and power button until it turns all the way off. Wait a couple seconds, then press the power button to turn back on)

Try wireless again.

If nothing, then

Obviously check and make sure wifi is on under settings.

If still nothing,

Try resetting your network connections:
Settings > General, then tap Reset > Reset Network Settings

If you can't see any wifi networks at all, you might have a bad wifi card in the iPad. Bring back to an apple store.

Here is a guide on how to convert DVD to iPad mini videos with the help of a DVD to iPad mini converter.

Hope it will help.