Hi @YunYing ,
Sadly, I can not access the code, as I do not have acces to your portal. (thats a good thing tho, security!)
It looks like you want to make a slider with vertical thumbnails. If you click on a thumbnail, a new “slide” is inserted. There are plenty of ways to build one!
A quick Google search gives back a complete slider with HTML, JS and CSS to copy, with the only difference that the thumbnails are on the right:
https://codepen.io/hashif/pen/xxbPLKx
Try to search for a codesandbox or jsfiddle example, that will most of the time give a complete example including code.
If you have a hard time building the examples into a working module, give me a message!