Dragon Realm is a fairly complex pack; combining that with the difficulty options means installation is not a trivial click, unpack, and run:
Set up a modpack instance; you are free to use whatever launcher or installation system you choose
Install Forge into your instance (process varies by launcher)
Unpack all mod files (both 'Reika' and 'other' zips) into your /mods/ folder; if this is a server instance, remove the client-only mods from the server side
Choose ONE "Configs and Scripts" package and add it into the root instance folder (so that its config and scripts folders end up in the proper locations)
Optional: Install Tyksera texture pack by adding it to the /resourcepacks/ folder
If installing on a dedicated server, remove all purely clientside mods. See "Mod List" for a full list
Add the following JVM arguments:
-DragonAPI_disable_ASM_RIVERGENLAYEREVENT
-DragonAPI_enable_ASM_NOOCWORLDRIFT
Set RAM allocation to between 3G and 5G on a client, 6-8G on a server
Change client configuration settings as desired. Optionally add or remove client-side mods (minimaps, FX mods, etc)
Open the DragonAPI config and change the "Expected World Center" X and Z and the "Expected World Size" options to ones you anticipate for your playthrough; they usually should roughly match the location of spawn and the distance of the furthest player's base from spawn
If desired (not recommended), re-enable MystCraft by renaming the jar from .jarx
If enabling MystCraft, open /scripts/tweaks.zs and uncomment (remove the '//') from the four lines changing the recipes for the MystCraft writing desk and Book binder (Mystcraft:writingdesk and Mystcraft:BlockBookBinder), around line 260
Launch the client/server with the DEFAULT world type; create at least one new world; ClimateControl needs to be initialized with a world
Delete that world; ClimateControl initialization breaks that world's biome map
Verify that the ClimateControl settings in /worldSpecificConfig match those in the "main" config directory (the values that exist in both files); if they do not, make them match and then repeat the previous two steps
Generate worlds as desired, always using the DEFAULT world type
