The first step in creating your own repository is to make a gpg key for your key signer. I find it best to separate out the key signing completely from myself and have a separate account for signing rpms.
[root@server0 ~]# useradd signer
[root@server0 ~]# passwd signer
Changing password for user signer.
New UNIX password: 
Retype new UNIX password: 
passwd: all authentication tokens updated successfully.
[root@server0 ~]# su - signer
[signer@server0 ~]$ gpg --gen-key
gpg (GnuPG) 1.4.5; Copyright (C) 2006 Free Software Foundation, Inc.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions. See the file COPYING for details.

Please select what kind of key you want:
   (1) DSA and Elgamal (default)
   (2) DSA (sign only)
   (5) RSA (sign only)
Your selection? 5
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
        = key expires in n days
      w = key expires in n weeks
      m = key expires in n months
      y = key expires in n years
Key is valid for? (0) 10y
Key expires at Sun 21 Jul 2019 04:32:53 PM EDT
Is this correct? (y/N) y

You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
    "Heinrich Heine (Der Dichter) "

Real name: Repository Signer
Email address: signer@example.com
Comment: Example Com
You selected this USER-ID:
    "Repository Signer (Example Com) "

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
You need a Passphrase to protect your secret key.

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.

...+++++
..........+++++
gpg: key 44CB93FD marked as ultimately trusted
public and secret key created and signed.

gpg: checking the trustdb
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
gpg: next trustdb check due at 2019-07-21
pub   2048R/44CB93FD 2009-07-23 [expires: 2019-07-21]
      Key fingerprint = BD7F E3E1 3403 3F35 5DA7  C8AF CC08 B6BA 44CB 93FD
uid                  Repository Signer (Example Com) 

Note that this key cannot be used for encryption.  You may want to use
the command "--edit-key" to generate a subkey for this purpose.
Next, export the newly created key to a file.
[signer@server0 ~]$ gpg --export -a "Repository Signer (Example Com) " >RPM-GPG-KEY-example.com
Now, import the key into the rpm database to verify everything is working correctly.
[root@server0 install]# rpm -q gpg-pubkey-*
gpg-pubkey-f51839ac-46362566
gpg-pubkey-b2980b13-3c1d0597
[root@server0 install]# rpm --import ~signer/RPM-GPG-KEY-example.com 
[root@server0 install]# rpm -q gpg-pubkey-*
gpg-pubkey-f51839ac-46362566
gpg-pubkey-b2980b13-3c1d0597
gpg-pubkey-44cb93fd-4a68c9c4