This clone feature works if you want to duplicate your website to an addon domain or sub domain in one cpanel account. so you don't have to bother to clone manually. but this feature is only available for websites registered with softaculous . here's the tutorial: please enter your softaculous cpanel
1. Click All Installation

2. Click the Clone website icon that you want to copy

3. Select the destination website that you want to copy. make sure the sub domain or addon domain folder is empty to avoid errors later. if there is still data, please delete it first and make sure it is empty. then click clone installation

wait the process usually takes less than 1 minute. then you will get a notification finished