From your Sync dashboard click Install on the left Sidebar. Check the box next to the sites where you’d like to install your plugins or themes. To install iThemes products, click iThemes under the Select Source section and then click either Plugin or Theme under the Select Item Type section.
Choose the plugins or themes you wish to install and click Install or Install and Activate. You will see that we now have an Installation Queue.
If you accidentally add something to the Installation Queue, you can click the X to the right of the product’s name and remove it. To complete the installation click the Install Queued Items button.
To install plugins from the WordPress repository, change the source to WordPress.org. Type in the plugin you want to install and click search. Now click the Install button.
You can also install your favorite WordPress.org plugins and themes from the iThemes Sync dashboard. If you do not have a WordPress.org account, you will need to register for one.
You can utilize the WordPress.org Favorite feature. Click here for instructions to set up this feature.
The final way to install a plugin or theme is to upload the .zip from your computer. Click the Upload button and navigate to your folder or simply drag and drop to the upload area. Find the zip you want and click the open button. Now click the install button and it will be on your site.