Importing a modpack from CurseForge
Before you follow this guide you will need to have already downloaded the modpack.zip of the modpack you want to import from CurseForge or if its a custom pack using the Twitch app you will need to export the modpack. Twitch has a guide on exporting modpacks here https://support.curseforge.com/en/support/solutions/articles/9000197912-exporting-and-importing-modpacks
Click on the instance you want to import the modpack to (https://www.creeperhost.net/help/docs/minecraft/instance/finding-your-instances) then make sure that the server is stopped by pressing the red stop button in the top right.
Next click on the Importer
link in the instance navigation
On the importer page click on Click or drag your twitch export to upload. This will open a window where you can browse to where your CurseForge modpack.zip is.
Click on the modpack.zip then click on Open
It will now upload the modpack, once the upload is done you will get a notification saying that its being installed and you should see a progress bar showing files being downloaded.
Once the pack has finished installing you will get another notification saying that your instance is ready to be used and you should be able to start the instance (https://www.creeperhost.net/help/docs/minecraft/instance/start-server)