/var/www/html/sp-metadata.xml
The entityId attribute specifies who we are:
<md:EntityDescriptor xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" entityID="https://your hostname">
<md:SPSSODescriptor AuthnRequestsSigned="true" WantAssertionsSigned="true" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">
The <ds:X509Certificate> element contains the public key that was generated earlier:
<md:KeyDescriptor>
<ds:KeyInfo>
<ds:X509Data>
<ds:X509Certificate>ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopqrstuvwyz01234567890+/A
ABCDEFGHIJKLMNOPQRSTUVWYZabcdefghijklmnopq==
</ds:X509Certificate></ds:X509Data>
</ds:KeyInfo>
</md:KeyDescriptor>
the "Location" xml attribute specifies the URL at which the IdP will post the user info after a successful login:
<md:AssertionConsumerService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://[your hostname]/Shibboleth.sso/SAML2/POST" index="1"/>
</md:SPSSODescriptor>
</md:EntityDescriptor>