After you installed the theme and slider plugin properly, you may still see the warning like these...
For Revolution Slider, it looks like this :
For Layer Slider, will look like this :
Please note that you can't put the theme's purchase code in that field. It will not work.
The purchase code( or activation code) for slider is not necessary. It's used for auto updater for the slider. However, the slider that's included in this theme is being used as 'Extended license', it's considered as a bonus file which doesn't support auto updater(and their slider templates.).
If you need to use auto updater, you have to purchase slider's regular license separately. But as we mentioned. It's not necessary, you can still use slider that come with the theme like its' regular license and we still keep pushing slider's update in future theme's version as well ;)