Help CenterFTB modpacks are some of the most popular Minecraft modpacks out there. These modpacks can be installed using the Feed The Beast App. Much like CurseForge, the FTB App is a mainstay for creating, downloading, and playing modpacks created by various users or yourself for Minecraft, hosting a variety of different premade packs ready for download at a moment's notice. This guide will briefly go over how to get a FTB modpack ready to play on both your server and your local installation!
📌Note:EVERYplayer on the server will need to join using the same modpack & version on the FTB App. Otherwise, they will not be able to join.
Step 1: Download the FTB App
First, you'll need the FTB App in order to be able to download and install your modpacks locally. You can find it here.
Download the app for whatever operating system you are currently using. Be sure to download the STANDALONE edition if you are not interested in downloading Overwolf with the FTB App!
Once you have downloaded the right version, open the file and follow the installation instructions. If you are having trouble, you may check the specific installation instructions for your operating system (as well as other, more specific information about the program) at FTB's website here.
Step 2: Installing Modpacks on the FTB App
Once you're in the main area of the FTB app, you can navigate to the search icon to begin your hunt for a modpack of your liking. For our example, we're gonna be installing StoneBlock 3!
🛑 BEFORE YOU PROCEED: In order to play a modpack on your server, you need to ensure that the version you install matches the version on your server. If the versions do not match, you will not be able to join the server.
To ensure they're matched up, go to the modpacks tab of your server, press the FTB Icon, and find the same modpack you're looking to install locally. In this case, of course, we're looking for FTB StoneBlock 3. Take note of what version you're installing on the server, as you'll need to install the same version locally!
In this case, we'll be installing v1.9.0
Find the version here that matches the version on your server and install it.
Step 4: Playing Modpacks from the FTB App
Head back to the home page. You should see all of your currently installed modpacks and their versions. This is a great time to double-check that you have the correct version installed! Hover over the modpack you wish to play, then press the big, green play button! 
Connecting to Your Modpack Server
Once the modded Minecraft launcher opens, hit play as you normally would to launch the game. You may need to check a box that states you understand the risks of playing a modded version of Minecraft. Click the checkbox, and you should be able to hit the green play button to open the modpack.
Once the game launcher, hit "Multiplayer" on the main menu. From there, hit the "Add Server" button to add your modded server.
Head back to your server's control panel on Panel.SimpleGameHosting.com. From here, log in to your account and copy the IP address in the top right corner of the "Console" page.
With the IP address copied, head back to the modded Minecraft game. Paste the IP address into the "Server Address" box.
You can name the server whatever you wish, as this is local to your computer.
Hit "Done," and you'll be taken back to the Multiplayer page.
You can now connect to your server. You may need to hit "Refresh" to ping the server again if the information doesn't automatically pull.
👋 From this point, you're ready to start playing your Modded Minecraft server!
Troubleshooting Common Problems
Dedicating More RAM to Minecraft Modpacks
If your client is crashing often, you may wanna try upping the amount of RAM you've allocated. To do so, go to the settings icon:
Then Instance Defaults. You can then increase or decrease the allocation there!
📌 A good rule of thumb for how much RAM you should allocate to Minecraft modpacks is to match the amount of RAM your server needs to run the modpack.
Generally speaking, 6000-10000 is the normal range for allocated RAM. Depending on your system's specs, you may even go further than that! Do be sure to experiment and find what seems to work best for you!