How to Install SCILAB ?

5.5.0.-2 is available from Repository. Is there a reason why you don't want to use that?

Because I think it is the latest one.

What is the output of:

lsb_release -a; uname -a

Thanks

Sir, the requested output of above command is:
-----------------------------------------------------------------------------------------------------
navin@navin:~$ lsb_release -a; uname -a
LSB Version: core-2.0-ia32:core-2.0-noarch:core-3.0-ia32:core-3.0-noarch:core-3.1-ia32:core-3.1-noarch:core-3.2-ia32:core-3.2-noarch:core-4.0-ia32:core-4.0-noarch:core-4.1-ia32:core-4.1-noarch:security-4.0-ia32:security-4.0-noarch:security-4.1-ia32:security-4.1-noarch
Distributor ID: Ubuntu
Description: Ubuntu 14.10
Release: 14.10
Codename: utopic
Linux navin 3.16.0-34-generic #45-Ubuntu SMP Mon Mar 23 17:27:54 UTC 2015 i686 athlon i686 GNU/Linux
navin@navin:~$
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What sensitive information about the version could be obtained from the "lsb_release -a; uname -a" command line?
 How to proceed?

OK, what is in the 5.5.2 that isn't in the 5.5.0 version that you need?

If you actually read the Spilsby webpage
https://www.scilab.org/community/news/20150401

You will see the difference ONLY affects Windows, which you aren't using. So, again, why do you think you need the version you manually downloaded instead of the one from the official Ubuntu repository?

Sir, usually the latest version of any application comes with bugs fixed and resolved issues with respect to its earlier version. That is my main intention. The new version has new graphics features such as the improvement of the fec function to enable the rendering of meshesAnd also I want to know the actual syntex of the command lines for any application/software by downloading and installing it. If it does not work properly, we have a facility in linux/ubuntu to uninstall ant revert to the edition availed by the official ubuntu repository. So I request you to guide me for the actual command lines to install scilab from this newest package. So that similarly I can apply the similar command lined to install any other application also.
Hope you can understand me. I also want to learn by this way!
Please help.

Extract the file then mark the resulting file as executable. You can then run the installer in the terminal (will probably need sudo for that part)

I'd just go for the version in the repositories. It will install easier and will upgrade when the repository us updated

Look at the web page of Scilab for installation instructions
http://wiki.scilab.org/Installation%20Compilation

Sir,
As per the link in #9, I applied following commands.
        (1) [$SHELL] wget http://www.scilab.org/download/5.5.2/scilab-5.5.2.bin.linux-i686.tar.gz
        (2) [$SHELL] cd <scilab-path>
        (3) [$SHELL] tar xzvf scilab-5.5.2.bin.linux-i686.tar.gz # For 32 bits systems

As a result of (1), the package "scilab-5.5.2.bin.linux-i686.tar.gz" was downloaded in /home/navin directory. It is of about 200 MB size.
After the I applied (2) as "cd home/navin"
And then to the resultant, I applied (3)

The process continued.
I want to understand that:
What process the last command (i.e. 3) did?
Where the resulting output stored?

NOTE: Before few days I installed three softwares named ---> Scilab CLI, Scilab, and Scilab advanced CLI. through USC. They all are of 5.5.1-7 Version. I could not find anywhere 5.5.2 version. -- Is it installed through above (3) command?

Read the man pages of tar, that explains the command (3).
You should see a new subdirectory now.

Through which command I can open man pages of tar?
How can I find location of the new sub-directory?

I strongly recommend reading some basic guides about using Ubuntu and Linux
e.g. https://help.ubuntu.com/community/CommunityHelpWiki and
https://help.ubuntu.com/community/ExternalGuides

You can see the man pages of tar with the command
man tar
Isn't that self evident?
A simple internet search for "man pages tar" would have provided thousands of links to web copies of that.

And the sub directory is created in the location that was your current directory when you executed the tar command. You should know best what your current directory was at that time.