Here is a quick presentation on how to use the products:
The Dashboard should be used for the Admin/CMS part of your website/platform:
Here is where you control everything from the management part, where you see stats like this about your products/users, where you edit/add/delete different items, etc.
This is the control panel of your site. The Dashboard also includes the Login Page, Register Page or Lock Screen Page so you can use them to have the access to the Dashboard.
The UI Kit should be used for the part where you present your business:
You can create with the kit the Landing Page of your startup/website, the Contact Us Page the Pricing Page the About Us Page etc.
Or you can use this to create your Blog, where you will keep in touch with your audience.
You can also build your own pages with already made sections https://demos.creative-tim.com/material-kit-pro/sections.html
If you create a SaaS, probably your users will have access to the Dashboard too, so they can control some items from there as well. However, you still need the UI kit for the presentation pages of your business/client. In this way, you will have the same design in the presentation and also in the Dashboard.