You downloaded a file named CrashPlan_3.5.3_Linux.tar.gz
file from the website and stored this somewhere on your computer. Open a termimal and go to the directory you downloaded it into and type
tar xvfz CrashPlan_3.5.3_Linux.tar.gz
This will extract the file. After it is done cd
into the directory it created and install...
cd CrashPlan-install/
./install
It will then start installing CrashPlan. From their website:
CrashPlan automatically starts up after installation and prompts you to create a new account. Enter the information and click Create Account. CrashPlan will send backup reports and notifications to the email address you enter.
Extra: there is a README file inside the directory. Notable:
NOTES:
1) CrashPlan for Linux uses the Sun Java Runtime Environment to run. If
you do not have the Sun Java Runtime Environment installed, CrashPlan
can download a version of the Runtime Environment and install it alongside
CrashPlan itself. This will not overwrite your system's installed Java.
2) Once installed, the GUI can be launched by using the command 'CrashPlanDesktop',
which will be linked from your chosen directory. If defaults are used, it
will be:
/usr/local/bin/CrashPlanDesktop
3) The background service, now called 'CrashPlan' which starts the
backup engine, will be installed and setup to run from your designated
directory. If defaults are used, it will be:
/etc/init.d/crashplan
and it will be linked from:
/etc/rc2.d
Note that on some flavors of Linux you may need to added the following to /etc/init.d/boot.local:
/etc/init.d/crashplan start