To add a course to your cart, go to the Smart School Online Course front page, then click on Online Course.
Here you can view the multiple courses, and in some courses, there is an “add to cart” option available below. Some courses are free; in those courses, the “add to cart” option is not available, but you can still access them for free. Now, click Add To Cart, and the course will be added to the bucket at the top right, as well as the count of your course that you added to the cart, which is displayed on the bucket. 
Now in this cart you can see added course and its price as well as you can see sum of total amount of all the courses which you added in the cart.
For buy course, click on Go To cart which is showing in below, cart list will be open,
here you can see the all details of the course as amount, discount, category and in left below you can see continue shopping option available, this option will redirect you the main page of online course and you can add the more course as well. Now click on proceed to checkout button which is showing in right, if you have not login online course, login module will be open then you need to login with your register email address and password then go to payment option and purchase the course.