After downloading the file (say, into boinc_5.2.13_i686-pc-linux-gnu.sh), type 
sh boinc_5.2.13_i686-pc-linux-gnu.sh
This will create a directory BOINC/ with the following files:
boinc
The BOINC core client
boincmgr
The BOINC manager
run_client
A script that cd's into the BOINC directory and runs the core client.
run_manager
A script that cd's into the BOINC directory and runs the manager.

The core client has a number of other command-line options.

You may want to automatically start the core client at boot time.

To control a running BOINC client, use the BOINC command tool. "; page_tail(); ?>