Learn how to import Ant Design System for Figma file to your Figma account.
I assume that you are already a happy user of Figma but if you don't have an account go to www.figma.com and sign up. If you need help with signing up, you can learn how to do it here.
If you're using the Figma Desktop app, any locally stored fonts are already available to you. For the browser version of Figma, follow this guide.
This UI Kit uses SF Pro Text font, and you can get it from here (macOS) or here (Other OS - click on the green dropdown button "Code" and select "Download ZIP"). Then install SF Pro Text fonts on your PC and restart your computer.
You can duplicate the file to your Figma account by clicking the link in the pdf you've downloaded.
If you are in a team and purchased the Team license of this product, you can publish it to your team library in Figma. You will find more information about team libraries in Figma and how to work with them here.