For required courses within credentials, you can set up your credential topics so users can take these courses at their leisure. When they open the credential, they will have the option to launch any of the courses directly from that page by clicking the drop down arrow and then clicking on the desired course.
You may find this more effective than the alternatives of assigning out all of the training via Create New Assignments or making all courses available for self assign via the Course Library (which allows all users to access them, even if it does not apply to to their individual training).
1. Under Administration click Manage Credentials, and then click on the credential you would like to edit.
2. Click the gear icon next to the credential topic.
3. A pop up window will appear. Check "accessible from user credentials" in the Requirements section. Then, click Save.
4. If there are multiple topics in the credential, repeat steps 2 & 3 for each topic.