Create cert, pem, and p12 files for your App. following this tutorial
Generate a certificate signing request. Use your own email address!
openssl req -new -key private.key -out CertificateSigningRequest.certSigningRequest
On the “What type of certificate do you need?” Apple page, say “iOS App Development”. Go through its little wizard and upload your
CertificateSigningRequest.certSigningRequest
file. It will give you back a DEV_APN.cer
file.