HTLib Data Pack
Custom raids are driven by data packs, so you need to prepare a data pack template first. See the data pack template download.
Your First Raid
Add the following JSON file named first_raid under the raid path to create your first raid. This raid has two waves and uses the mod's built-in presets.
Raid Item
Summoning raids via commands can be cumbersome, so the mod also provides summoning items.