After you download the package from ThemeForest named DukaMarket Theme v1.0.0, please unzip it. You’ll see a file called DukaMarket Theme v1.0.0. Inside, you will see a zip file: dukamarket.1.0.0 which needs to be uploaded and installed.
Now that you made sure WordPress is up to date, you can install the theme via WordPress
Install the Dukamarket theme via WordPress
Step 1 – Log into your WordPress website and go to Appearance > Themes and click Add New.
Step 2 – Click Upload Theme.
Step 3 – Browse the dukamarket.1.0.0.zip file on your computer and click Install Now.
Step 4 – After the theme was uploaded successfully, click to activate it.
