Step 1: Login to your WordPress admin panel and navigate to Appearance → Themes
Step 2: Click Add New button at the top of the page, then the Upload Theme button on the next page.
Step 3: Select grafton.zip included in the files downloaded from Themeforest and click Install Now
Step 4: Once the file is uploaded and installed, click Activate
Step 5: At this step, you will open a theme installation window, which consists of several steps, the first one will be a greeting, after that you will be asked to install the child theme, whatever your choice, you can install plugins and demo content. About this in the following article.