You can either create your certificates by makecert or by OpenSSL. And this How to Setup a CA gives you an easy tutorial of creating certificates hierarchy by OpenSSL. First is the root CA certificate. For experimental cases, makecert is enough. But for product, you may want to use OpenSSL or apply a certificate from CA like VeriSign.

makecert -n "CN=TestCA" -r -sv TestCA.pvk TestCA.cer

And import the root certificate to the system certificate storage of Trusted Root Certification Authority. See this article.

Then create the certificate for your HTTPS web site.

makecert -iv TestCA.pvk -n "CN=TestSite" -sv TestSite.pvk -ic TestCA.cer TestSite.cer -sr LocalMachine -ss My -sky exchange --pe

If you will test your client app on a machine other than the server machine, you have to import the TestCA.cer to the client machine as well. So that the client machine trust TestCA (the root cert), it will also trust the server certificate (TestSite).

Hosting an HTTPS site, you must have a certificate with private key. But the last makecert command creates the private key in TestCA.pvk which can't be imported to the system storage directly. We have to convert it to .pfx format

pvk2pfx -pvk "TestSite.pvk" -spc "TestSite.cer" -pfx "TestSite.pfx"

You have to import TestSite.pfx into the Local Computer Personal Certificate store.