In order for you to efficiently develop your apps, it's a good idea to have your prototype app on your actual device ... also how cool is it to see your functioning app on your mobile device?
In order for you to do this you'll need to have two Apple certificates. This is no problem. Go to your Account page on the Apple Developer website and you'll see a "Certificates, IDs & Profiles" tab. Click on it.
Right now, we're going to gather two different things - a development and a distribution certificate.
On the Certificates, IDs & Profiles page, on your upper right you'll see a "+" button - click on it.
Now you should see this page. Choose iOS App Development under Development for your certificate type then click Continue
Next page will be about creating a Certificate Signing Request (CSR)
Now we need to generate a CSR with Keychain Access. Way up, on the upper right where your status bar is, you see a magnifying glass icon, this is Spotlight. Open Spotlight, then type in Keychain Access then open it up.
Alternately you can go through the Finder search system
When the program is open, Go to the drop down Keychain Access menu > Certificate Assistant > Request a Certificate From a Certificate Authority
You'll need to enter your e-mail address and name. Make sure you choose Saved to disk not Emailed to the CA then click Continue
You can save it anywhere on your computer, I choose the Desktop.
Great! Ok, now go back to you Development page at the CSR page you were at, then click Continue at the bottom of the page
Alright, now you are going to find that CSR that we just got and upload it.
Hit Choose File...load it up and click Continue
Alright, you should now see this page. Click Download then find the file (probably in your Downloads folder) and open it up by double-clicking. It should open up Keychain Access. If nothing happens, it was probably already added, if not and an Add certificate screen popped up for you, just click Add.
Now since we have a certificate for our development profile, now we need one for our distribution profile. We going to do this process again but this time it'll be much easier. Now, click on the Add Another button.
This time under Production choose App Store and Ad Hoc
Continue on just like before, you can reuse your CSR file! Once you've gone through that process again, you're all done.
You can exit the Keychain Access screen.