There are two things that you should check to see if your students can see your Blackboard course site.
First, check to see if your students have been enrolled in your site. To do this, go to your Control Panel and click on Grade Center, then click on Full Grade Center. If you see your students in your grade center they have been loaded into your course site.
Second, you will need to check to make sure that the course is Available to students and what your date restrictions are. To do this, click on Customization in your control panel. Then, click on Properties. From here you can check in sections 2 and 3 to make sure that the availability is set to Yes (if you want your students to see the site) and that the date restrictions are set to the appropriate dates. Once you are finished with any changes click Submit.