When you first start off, change your keybinds. Some are ill-configured and need to be changed. Some notable ones:
Mekanism Mode (Armor/Item) Switch - Important
Sprint Key - Conflicts with a bind called key.control. key.control is pointless.
Skills Key - Broken with a few keybinds, this is a must for Advent of Ascension.
Wand Focus - Good if you use Thaumcraft.
Afterward, make a world. You will get a Crystal Ball. Chuck that in storage for later. Get a house and living standard set up. Move away and use the crystal ball, follow its instructions. At the end, the "Destiny" is pointless, but choose none for the best effect. Move on and live! If you play on a server, you can use the crystal ball immediately without any consequence.
This modpack is meant to be played with friends. Get a server and Race to Space!