Q:

How to install Chromium .zip file?

I have the zip file but I don't know to install it from a .zip file. Here are the contents of the extracted chrome-linux.zip file:

A:

A .zip file is an archive, so you can't install it, but can unzip or extract it - right click, select 'Extract here'. Call it installation if you like, but that's pretty much it.
If you prefer the terminal way, then:
unzip chrome-linux.zip -d /destination_dir

To run it cd to the installation directory, and then run ./chrome
Needless to say, I'd strongly discourage using any unofficial version of Chrome. It could be unsafe, and your best bet is to get the real thing instead.

