A simple collection of various mods, some of which do require minor configuration to work properly if you're wanting to play singleplayer or host a server. If you're just downloading this to join a server that hosts the modpack, you won't need to worry about these. Off the top of my head, here are the ones to pay attention to:
—Badmobs config file. Just open the profile folder for the modpack, go to the config folder, find the file for badmobscommon and make sure you switch out the spawn condition for creepers, spiders, skeletons, endermen, and a few other overworld enemies to be false. This is the zombie apocalypse, after all!
—Lost Cities mod. This one's actually pretty easy. Whenever you're setting up a new world, go to the More options and you'll see a button to enable the Lost Cities generation. You can customize it with a lot of parameters, so it might be good to play around in a creative world first to see if you like its generation.
If that sounds easy enough for you to manage, then I'm sure you'll love this modpack! There are guns, planes, and plenty of zombies, so make sure you explore all your world has to offer!