You have to activate the theme license key before installing the required plugins.
Go to (Your Theme Name > Product Registration)
Please follow the below process step by step to activate the license.
1. First, put your license key in the License key blank field.
If you can’t find the license key then this article is for you.
2. Checked the box on the left side of the consent description.
3. Click on the Activate License button.
You will see the License Activated notification on the top like this below. Thats means Congratulation! Your license is successfully activated.
4. Click Save Changes Button
Note:If you got the License Activate another website message after activating license then you have to deactivate the license from the previous domain. Next, you have to activate the license in your new domain. Because our license is a one time only use license code so you can’t use them on multiple sites. You can check Envato License Policy