You can install a new WordPress theme without having any technical knowledge. Its so easy and automated.
1- Login to your WordPress admin dashboard.
2- Under the dashboard menu, hover your mouse on Appearance and then click on Themes.
3- Click on Add New.
4- In the Add Themes page, you can search for a theme or browse the themes from Featured, Popular, Latest options. If you hover your mouse over any theme, you will be presented with two options - Activate and Live Preview.
5- Hover your mouse on any theme you like and then click on the Install button.
6- A newly installed theme will show you the Activate option. Click it!
Congratulations, you have installed and activated a new theme on your blog.