A few basic things to keep in mind if you'd like to not die every 30 seconds when starting out on the server.
This world is not easily inhabitable.
The moment you reach Earth's surface from the Spawnpod you will be met by hungry cannibalistic zombies, ghouls, skeletons, and even human mobs. They want your flesh , and many have guns they will use on you to get it.
The ecosystem's weather is extremely erratic, and prone to create tornados. It's not wise to build structures with light materials like wood. Blocks made of heavy stones or metals will stay in place through the heavy winds.
You need to hide. Some of our players will be happy to help you start off, others may just kill you. Regardless, it's recommended you dig a nice little hole in the ground and mine some basic ores so that you have enough materials to get some basic machines set up and get better weapons and armor. To start, you'll want a Hand Cannon.
So, now that you made yourself a Handcannon, you can start shooting back, after crafting yourself some stone bullets. But that thing isn't gonna help much. You'll need to make a better gun from @TechGuns and make your own ammo for it. To make sure we always have enough materials, we'll need to build our own factories from @Mekanism.
Factories need power to run, and to start creating power we can build a Heat Generator, which creates energy from lava beside it, and can burn Fuels to create power as well. This generator is very inefficient and wasteful, but a start.
You will also need to build and provide power to a Metallurgic Infuser, which is a machine that will produce Enriched Alloys, Electronic Control Circuits, and Steel.
P.S. The Blast Furnace from @TechGuns makes steel with a 4x cheaper coal recipe.