To install, we need to inflate the downloaded archive first using the "gunzip -d archive.tar.gz" command followed by extraction of the resulting tar file using "tar -xvpf archive.tar" command. Successful execution of these two commands for the 2.2.15 archive will create a "blast-2.2.15" directory with bin, doc, and data subdirectories under it. For better database management, we can also create a db subdirectory for using "mkdir blast-2.2.15/db" command.