How to get the mod pack and optionally join the server!
1. Firstly make sure that your system is running Java JRE 8 as 7 (or below) won't work! So get the Java JRE 8 version if your system isn't running it! If you need help with this step and/or getting it installed PM me and I will do my best to help you get Java JRE 8 running for you.
Here you see that my Linux OS clearly have Java 8 installed
This screenshot is showing what you should end up at to download the launcher.
3. Once it is installed you will want to allocate the RAM to 768MB (or more) min and 1.5GB max (or more but don't be giving the game more than 4GB or else your CPU won't like it! Unless your running HEAVILY shaders or some other intensive textures.) Make sure that also the Java version is correct (it should read 1.8.xxx) as well as the file path. Usually the game works best if you directly point it to the ~/jre/... file path. All of this can be done on the Java section of this launcher.
Here is minimally what you should end up with (Permgen is not used at ALL for Java 8+ so you can safety ignore it or just set it to 64MB like I did). File path may vary from OS to OS but just be sure that it pointed at the ~/jre/... directory/folder and you should be good to go!
4. Add your user account (top right hand side and click "add")
Here as it says just click "add" (even if there no accounts there) and fill in your login details.
Importing is simple really. Just click on the "paper" on your far left of the top screen and click the "Import Modpack". You may download it directly by providing it the link (the download link) or simply looking it in your system once you downloaded it yourself!
6. Click launch on the imported instance and you are ready to play!
Click on the instance to "highlight" it and then simply click launch. You will presented with a standard main menu. Plus the "Last Server Joiner" mod's button. Once you join the server as usual (Multiplayer screen) at least once you will be able to use this button to connect to it again!
7. If you wish to join the official server then it should already comes shipped but failing that the server IP is accessiblecraft.mcnode.net
If your needing any help doing ANY of these steps PM me and I will do my best to help you get your game going!