UI kits can be a terrific way to jumpstart your product knowledge whether it's for a product you've not used before or just a brand new feature and one you're quite familiar with. The UI kits available for Adobe XD definitely strike the balance of both.
To access the latest UI kits you can either come to the file menu and select get UI kits. Alternatively, in the home screen if you click the add-ons tab here on the left hand side and then click the UI kits it will open up a web browser. From here you can see UI kits that are OS specific towards the top and then towards the bottom a series of different designs.
I'm going to scroll all the way to the bottom here and select one of my favourites which is attractive by Cody Brown. From here I'll go ahead and download and open up the file. I'm here in Adobe XD and like most UI kits I have both examples of real world designs with design elements in use here towards the bottom and then towards the top the basic so colours and fonts that are in use as well as components that occur in that real world flow towards the bottom.
Another handy way to access some of these elements is to open up the assets panel on the left hand side. Here I can see all of those colours fonts and various components that are in use on the design canvas available to drag into new artboards as I build out my own design. UI kits are often a great way to deep dive on a new feature that you may be less familiar with like component states and auto animate for micro interactions, so you can look for those capabilities within the UI kit as well.
Finally it's really easy to change fonts and colours throughout the kit simply by coming into the assets panel here towards the top and selecting, let's say a colour, that's in use on that design canvas. When I right-click and select Edit I can come in and dramatically change that colour value. Notice that the change that I made here in the Properties inspector for that individual colour propagated to all instances of that colour on the design canvas. You can do the same thing for any of the character styles in use within the design and change all of these elements to be more in line with a project you might be working on.
I think you'll agree that UI kits can be a wealth of knowledge as you acclimate to the XD application. I encourage you to give it a try.