Installing Exscribe should generally be easy. If these instructions are not sufficient, feel free to email mattcasey at users.sourceforge.net for assistance.
You must install php and postgresql before trying to set up Exscribe. This process varies a lot depending on the system and is outside the scope of this document. Once postgresql is installed, you must create a database. Use the 'createdb' command to do this. I generally recommend adding the user 'www-data' to the database to make connecting easier. See the postgresql documentation for help with this.
Copy all the php files and subdirectories to somewhere available to the web server (often /var/www or ~/public_html or ~/htdocs). Edit config.php that was just extracted (Documentation in the file should explain each value). The database name and administrator name are especially important.
In a web browser, navigate to setup.php that you just extracted. Read the instructions there and build the database tables (if you edited config.php correctly, it will go well).
Now you can log in and go to the administration page to set up a new blog. Don't forget to change your password!
Matt - 12/21/03