Magento 2 is the awesome e-commerce platform. We can download a lot of free Magento 2 themes,
once you get nice free theme for your store then just follow the steps for your Magento 2 theme installation

Let’s Kick Start Now.

Download Your Theme

Download the zip file, it will contain your theme. Then unzip the file, now you can see two directories: app and pub.

Upload Your Theme

Open root directory of your Magento 2 store. Magento 2 free theme will have app and pub folder, you just move this both folder in your store root directory
Now you can use FileZilla or manually upload.

Finally Run Commands:

First, upgrade the setup by running this command:

php bin/magento setup:upgrade

Deploy the static content by running this command:

php bin/magento setup:static-content:deploy

Finally setup your theme in your Magento admin panel.