Welcome to iMore.com!
I'm no longer using an iPhone but I have used Fitbit with iPhone previously, albeit the Charge HR. I do currently have the Surge connected to my Android device.
Start by downloading the Fitbit app from the iTunes store. I'm guessing you already have a Fitbit account? If so, sign in on the app. If not, it's probably easier if you go to Fitbit.com and sign up there, then log in to the app. It will then walk you through connecting your Surge.
I would probably only connect it to your phone, and not both ipad and phone. You can download the app on your ipad and once you log in it will sync with your account. So you'll still be able to see your Dashboard and stats on your ipad, but you may run into sync issues and it may kill the battery on your Surge if you're trying to sync to 2 devices.
I have my Surge synced to my phone, and on my laptop I have the Windows 10 Fitbit app signed in to my account. It isn't syncing directly with my Surge, but rather with the Fitbit cloud. I can see all my stats on my laptop app, but it isn't connecting directly to my Surge, if that makes sense. And it updates pretty quick when the Surge syncs with the phone app.
Please join the site so you can post a response or ask more questions here in this thread. It's easy, here's how...
http://forums.imore.com/ask-question/293812-guide-how-sign-up-imore.html