At first you have to search the plugin,so you have to go plugin section from dashboard.
Then You have to choose Add New
On search plugin option you have to type "Reactive lite".then click on Install now.Then click on activate,it will be activated.
Install from wordpress back-end :
- Go to wordpress Dashboard-> plugins -> add new.
- From here click upload plugins button, then you will find the plugin upload window.
- Upload 'reactive-lite.zip' then click install now button.
- After successfully install the plugin then active it.