After you download the package from ThemeForest named Boutique New v2.x.x.zip, please unzip it. You’ll see a file called kute-boutique_v2.x.x.zip, 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 Boutique – new 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 kute-boutique_v2.x.x.zip file on your computer and click Install Now.
Step 4 – After the theme was installed successfully, just click to activate it.