It seems like your wplms theme has plugins folder empty, please download the fresh wplms package and then try the plugins should be present in the plugins folder in the wplms theme.
For one click setup refer:
https://www.youtube.com/watch?v=HURLXtbfKVY
If you want to install like demo 1, 2 or 3 then refer:
https://wplms.io/support/knowledge-base/one-click-setup-wplms-demo1/
If you want to install the modern child theme, then first install the plugins and upload the modern child theme in the wp-content/themes folder. Now activate/install the modern theme, refer:
https://www.youtube.com/watch?v=Au83kJuMDIc
PS: Please create your own topic in the relevant forum if you face any issues, this will help in faster responses and better understanding.
Since this is a very old topic so I am closing this topic, please feel free to create your own topic if you face any issue.