Step 1: open your Dashbord
Step 2: Click on Appearance >Themes
Step 3: Click Add New
Step 4: If you have a download file you can upload it
Step 4: If you want search Themes .Go to search and type what you want to search like if you want a Themes for News you can just type News and a list of Themes will display you can select your Themes
and click on install and Activate .