Copy the files in the plus disk folder (プラスディスク) over the files in the original game folder (東方の迷宮). Then install the 2.04 patch. You may need to install font hgrpp1.ttc
To patch the game to English, extract files from thLaby text files.rar into the Labyrinth of Touhou directory and run replace.bat. The replacer takes a long time and will likely slow down your computer significantly, so it is advised you start it and find something more productive to do for ~15 minutes than staring at your monitor.