From this post, I'll teach you how to download the lecture slides of the particular subjects that you are following.
Go to the Course Web, http://moodle.sliit.lk/ .
You need to login to your account to download the lecture slides. Then, scroll down and select the particular semester under your Course and Year. Then the subjects will appear.
Then select the subject that you want to download the lecture slides. You need to have enrolled yourself for that particular subject in order to download the lecture slides. If you don't know how to do that click here . I hope now you know it. If you have already enrolled yourself, the course material will appear. Then you can download them with a single click.