If you are upgrading from a previous version of Gallery, please see the Upgrading Guide.
Gallery 1.x requires certain programs to be installed before it can work correctly. For information on how to install these programs, see the installing required programs guide.
Decompress Gallery by using WinZip (on Windows) or tar (command line *nix). When it's finished, you should have one main gallery/ directory under which all Gallery files are contained.
Create two blank files in your favorite editor (e.g. Notepad, vi, emacs, nano, etc...)
Call one .htaccess and the other config.php. Place these inside the base Gallery directory.
In Notepad, be sure to select "All Files (*.*)" when saving the file, so the file does not have a .txt suffix. .htaccess and config.php will not work if they have a .txt extension
Upload the Gallery directory (which should now include config.php and .htaccess) to your server using an FTP program (like WS_FTP, CuteFTP or Fetch). Upload all files in BINARY mode. Also be sure to keep the directory tree and the case of filenames intact.
Create a directory on your webspace called albums.
Gallery will use this directory to store the albums you create and the images you upload to those albums. For ease, put the directory inside your Gallery directory.
Gallery requires some files and directories to be set writable by the web server. If you are unsure of how to chmod files, see information listed at http://www.eclecticpixels.com/tutorials/chmod/. Chmod as follows:
chmod 777 albums (this is the album dir created in step 2)
chmod 666 .htaccess
chmod 666 config.php
chmod 755 setup/ (setup/ is a directory)
Run the configuration wizard, as described in this guide.
Enjoy your new Gallery!