This guide will also apply to the various mod packs that come with FTB (DireWolf20, MindCrack, MagicWorld, etc) so just adapt it to whatever mod pack you are using. This guide can also be used with most other mod packs out there from Technic and ATLauncher as the general installation steps of most mod packs are similar.
3. Extract the files within the compressed FTB server zip you downloaded.
4. Upload all the files to your main server directory.
4a. Select all the files/folders that you uploaded for FTB in the FTP window, right-click in the window to bring up the context menu, and select "File permissions". Change the numeric value setting to "755" and check the "Recurse into subdirectories" making sure "Apply to all files and directories is selected" then hit OK. Wait for the process to complete. Note: It might have 755 selected already, but continue with the process anyways to make sure all files are set to 755.
4b. Move the FTBServer.jar (or whatever the server JAR file is named) file into the "jar" folder. If there is more than one JAR file (ex: minecraft_server_1.7.10.jar and forge-1.7.10-10.13.2.1291-universal.jar), move all of them into the jar folder as well (don't move JAR files from within any folders such as the "mods" folder). Move the "libraries" folder to the "jar" folder as well if the mod pack has one.
5. Log into your game panel and change the "JAR File" selection to "FTBServer.jar" (or whatever the server JAR you uploaded to the "jar" folder is named).
6. Hit the "SAVE" button on the bottom of the panel and restart the server.
7. Your server should now be running on FTB!
*Note: FTB causes problems with the Multicraft online status detection, so it may display a blue circle icon instead of the usual green circle even though your server is online.
Updating Your Mods
In order to update your server's mods, you will need to delete all existing mod folders and files to do a clean install. The files/folders are commonly the following:
redpower (could be in jar folder)
libraries (in jar folder)
As mentioned above, it is usually best to install mod packs on a completely empty server (even for updates since they are simply full installations with newer files). Once those are deleted, simply follow the above directions to do a clean install.