User blog comment:Gen. Grievous1138/Mount Gundabad/@comment-25841881-20151224210128/@comment-25841881-20151225045154

World files aren't that large of a file size, they actually are quite small, if you haven't generated like every chunk on the map.

For the instructions, prepare to have fun, General(This is the simplified version with shortcuts and stuff!):

Open your technic launcher.

Select the modpack.

Click on the modpack options gear.

To the left of the install folder textbox, hit "Open."

Open the saves folder within that folder.

Find the name of the world in that folder. That is the file you want to upload.

Copy and paste that folder into somewhere easily-accessible, like the desktop.

Compress that folder.(Right click on it and press "Compress")

Go to Dropbox, or whatever file hosting you prefer, like Google Drive.

Upload the file.

Get a sharable link.

That link is what you will give people, and they will be able to add that world, through pretty much the opposite of these steps.