How to get my glitch.edgeapp.net point url?

How can I get my pointing urls without adding a domain. I want to point another domain to multiple projects.

If you own example.com, you can get a point url for api.example.com by adding the domain to a Glitch project.

so I am able to put api.example.com in one project and then dashboard.example.com in another?

Yes you can do that.