WikiTree does not access anyone's DNA. If you are asking how to make your DNA show up on your profile and then those of your ancestors, here is the process. On the top right of most pages, click on the "Add" button and then click on DNA which is the first item. Follow the instructions to add your testing company and your username for the DNA test. Be sure to Save. In a few hours to a day, it will show up on your profile and will show on the appropriate ancestors in about 24 hours.
I hope this helps and welcome to WikiTree!