Instructions
Click the link to the version of Rei's Minimap you want to download (see Resources). Download the file. You may need to click "Skip Ad," depending on where you download the mod.
Right-click the ReiMinimap file you downloaded. Open the mod files with an archiver program such as WinRAR, 7Zip and WinZIP. Follow the prompts in the program to open the mod files.
Hover over the upper-left corner of your start screen, click "Search." Type "%appdata%" and then open the ".minecraft" file.
Open the "bin" folder, then right-click "minecraft.jar." Open it with an archiver program. Both the mod file and the minecraft.jar file should be opened next to each other in different archiver windows.
Highlight all the ReiMinimap files in the mod folder and copy them to the minecraft.jar file.
Scroll to the META-INF folder and right-click it. Click "Delete" to remove it.
Return to the .minecraft top folder. Right-click in the folder and choose "New Folder." Title it "Mods."
Drag the zipped ReiMinimap mod file into the folder. Run Minecraft to use the game with Rei's Minimap mod.