If you want to enrol students into a course then you should move away from the front page and enter the course that you want to enrol the student into. Then from the menu that you showed before you select "More" at the bottom.
Then click on the "Users" tab.
Then as you can see there is an "Enrolled users" link. You can enrol users from that page.
Thank you very much for your post which was very helpful. However, I do not yet have the problem 100% solved. I managed to successfully find the "Course Administration" tab as shown in screen capture below. I enrolled a fellow named Jack with a STUDENT role assigned to him.
I then went to Site Administration where I find Jack's account profile and then I selected the "Log in as" link to login as Jack. Here is the problem: when I go to the Course I just enrolled Jack in I get this error message, "You can not enrol yourself in this course."
What control setting in Moodle do I need to change so Jack can have access to the course without seeing the "You can not enrol yourself in this course." message?
My guess was to try changing the "Self Enrollement" setting parameter to see if this eliminates the "You can not enrol yourself in this course." message. Unfortunately, after making the change and testing it out I still got the same "You can not enrol yourself in this course." for Jack. Additionally, the popup window is not helpful as it relates to whether or not it is suppose to fix this problem.
In short, any help that will target on a fix to this "You can not enrol yourself in this course." problem in Moodle 3.3.2 running Essential Theme will be greatly appreciated. Thanks in advance for any help.