How can I download a app with more as 100 MB via cellular?

Hello everybody!

I have since one week a iPad Air 2 (the first apple-device). I love it very much, but I have one, big problem!

I don't have wifi, but I have an unlimited 3G connectivity.

How can I download a app with more 100 MB via cellular? I read that I should turn off the device when loading the app and then back on, but it doesn´t work on my iPad. I have the iOS version 9.3.5.

The apple-support could not help me also...but its a really big problem for me, because I don't have wifi and so I can't downlaod many of apps....

Hopefully you can help me.

Sorry for my bed english..I hope you understand my problem ;-)

Greetings from Austria

Verena