What you'll need
Click a link in the UI Kits section of the Welcome Screen, or from the File or hamburger menu, to download the UI Kit you’d like to use. Depending on the resource, the download file will either be an .xd or a .zip file. If it’s a .zip file, uncompress it to access the .xd file.
Open the .xd file (File > Open) you downloaded. You may get a message that you are missing fonts. Install the fonts provided in the .zip file to update your design. If you are using Windows, you will need to close XD then install the fonts.
UI kits consist of artboards with UI elements you can reuse in your designs. You can rename the file and continue to complete the design. Or, you can copy and paste elements from the UI kit into your own design. Update the colors and design elements as necessary. Click the Assets icon in the lower left to open the Assets panel and speed up your workflow with reusable color swatches, character styles, and symbols.
Be sure to check out Lay out and design your app or website for more information on how you can use the Assets panel and UI kits to update your designs in Adobe XD.