Go to minecraft.net and find Download on the front page. Click on it. You will see Minecraft for Windows. You know this is not your platform, so you click on Show All Platforms, which is located under it. You proceed to find the Mac version of Minecraft. Download, and enjoy!
Hope this helps,
--Horn943
To open the Minecraft .jar file on a MacBook Air, locate the file in your Applications folder, then right-click and select "Open With," choosing "Java" or another compatible program. To install Minecraft mods, first ensure you have Minecraft Forge installed, which allows for mod compatibility. Download the desired mods, then place them in the "mods" folder located in the Minecraft directory (found under ~/Library/Application Support/minecraft). Finally, launch Minecraft using the Forge profile to enjoy your mods.
You have to open it with winrar.
You need to have java 6 or later installed on your mac for a minecraft server jar to open correctly. If this doesn't work you can use a terminal command to run the jar.
premium: get the 1.0.0 Minecraft jar here modsforminecraft.com/ and delete the Minecraft jar that you have and put the 1.0.0 jar in
When you open the .jar, you're then in the root, meaning the top 'level' which contains all the other folders and files.
You download the mod and open it with a archiving program, Win-rar is what I use but there is also 7-zip, then you have to find your .minecraft folder. You can find it by searching %appdata% in your start menu. Open the .minecraft folder then open the bin folder. Inside the bin folder, there is the .jar. Open it with a archiving program. Look at the mod. If there is a Readme file, open it and follow what it says to do. Also, there is usually the instructions on the page that you found the mod. If there isn't a Readme folder, then open the mod with the archiving program and copy all of the .classes into the .jar or your .minecraft folder. Caution: If you get a black screen when opening minecraft after installing the mod, then it is because you didn't delete the META-INF folder in your minecraft jar. Hope this was helpful. Ask me if there is any other problems. -Aiya
on windows on the folders thing at the to type in %appdata% then go to .minecraft than bin then delete the minecraft jar in it then put the 1.4 jar in
download minecraft forge, open it up and keep forge as is and hit ok, then find a mod, download the jar, and locate your minecraft folder go to mods folder, open that up and drag the mod jar into the folder and enjoy your mod. P.S. go to edit profile on minecraft launcher page and go to: use version, then scroll all the way to the bottom and click on the forge thing and then hit play and enjoy your mod.
MinecraftServer.exe/jar
Install the Java Runtime Environment (JRE) for your operating system, then open the Structure Planner Jar file.
You need an a jar from alpha stages, which you can get with Minecraft Nostalgia.
download it then chuck its contents in a mods folder in minecraft .jar