All good! It sounds like you are just going to use the digital signature to sign your program (I wasn't sure from your last post). What this provides is a guarantee that your program is made by someone who can be verified. More general information about digital signatures for code signing can be read about here: https://msdn.microsoft.com/en-us/library/ms537361(v=vs.85).aspx
There are 2 ways about this. You can create your own self signed certificate - which will honestly not do much good as it can't be verified.
Or you can pay a certificate authority to sign your certificate, however you will most likely have to pay around ~$150 a year or so and send them identity documents to prove who you are.
More information about getting a certificate can be found here:
I would highly recommend getting a certificate if you are planning on selling/releasing your product on the web.
At the moment I see Microsoft isn't easily providing a list of CAs, you can find a good list here: https://en.wikipedia.org/wiki/Certificate_authority
I personally like Digicert, however there really isn't any difference between them.