If you have questions about using mojoPortal, you can post them here.
You may want to first review our site administration documentation to see if your question is answered there.
How do I get to the log in page from Visual Studio 2010. Most application use default and/or master page.
If you want to review the code for the Login page, the files are in /Secure which can be found inside the mojoPortal.Web project.
If you want to merely login to your dev site, you will have to build the solution and then login by browsing to the dev site /Secure/Login.aspx.
You may be interested in the many development videos we have, they will answer a lot of questions.