I navigated to the File Manager — > public html (or www, which is the same)– > myblog — > wp-content — > themes. To enter the folder in the File Manager you have to double-click on the folder symbol.
When in the right side of the file manager the content of the folder “Themes” appeared, I clicked “Upload” in the upper line.
I have uploaded the zip archive of the Atahualpa theme. It didn’t work until I had extracted it. I clicked on the Extract button. The extraction dialogue appeared.
The paths were written into the boxes automatically. So I didn’t add anything. The File Manager created a new directory called “Atahualpa” and extracted files in it. Note that the archive with the theme should be comprised of one folder named as the theme. In this case the extraction will be correct.
I entered the admin panel of my site which was located at the address www.testing.2by2host.com/myblog/wp-admin and found the “Manage themes” option (Appearance — > themes). I had new theme among the available ones, and had to click “Activate” to make it current. At the very top of my admin panel I clicked “Visit site” link to see how my blog had changed.
So, I had installed three different WordPress themes using three different methods.
Now I could switch between the uploaded themes in my wp-admin panel by simply clicking “Activate”.