Why am I unable to install a theme on a web server?

Hi Community,
My name is kithen lovn, I want to use themes on my web sever and shift my local logo or pics on him, but never knows about or its terms , I want to know how to turn our profile into and many more like this kind of camping spy themes. i want this kind of .I am also confused about choosing which one is better for me
Anyone here can guide me on how can I publish and other useful information that’s help me.
Thanks in advance.