Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Try this first, to see if it makes any difference:
1. delete the app (force-stop the install if needed.)
2. restart the phone
3. once it has started up fully...
4. ... verify the connection to internet.
5. Then, when all that's done, install the app anew.
If your app is just 'waiting' when it tries to install, then it is running into some obstacle, and waiting for it to be removed. Do you have any security software on your phone? if so, it may be prompting you to 'authorize and continue?' or the like. And, if you look for it, perhaps that prompt is in another window? (I don't know what your phone is, so perhaps this advice does not apply... but it's a good guess, I think.)