Creating an NPC Statblock
The NPC Maker can be found in the your NPC Library, where a new button is available, labeled "NPC Maker". This button will open the NPC Maker window, allowing you to create, adjust, or merge NPC's. Be sure to hover your mouse over sections you are not sure of, there are lots of tooltips to tell you what everything is.
I highly suggest reading through the Creating a Monster Stat Block section from the Dungeon Masters Guide, Chapter 9: Dungeon Master's Workshop - Creating a Monster Stat Block. (link found above if you own the module). While many factors are automatically calculated, you will still be required to adjust your CR Modifiers (HP, AC, Attack Bonus, DPR) if working from scratch or dropping in an NPC stat block.
While some monster features are automatically calculated for, others will need your input instead. Anything automatically calculated will be displayed below the CR and Effective Stats section of the NPC Maker's main tab.
When adjusting CR Modifiers, try to keep the following in mind:
- If a power makes it more difficult to hit the NPC (imposed disadvantage, shield of faith, barkskin), add to the AC Modifier. (if the effect is like that of the spell "Barkskin", add the amount given by the effect; otherwise disadvantage might give +4, and teleportation might give a +2)
- If a power heals, avoids damage, adds temporary hit points, then add to the HP Modifier. (This one is tricky, but for spells like invulnerability, add the NPC's HP to the HP Modifier. If the effect is like that of a healing spell, add the average of the maximum number of times the NPC can cast the spell; otherwise try to compare to the chart for monster features in the link at the top of this page and use your best judgement. Don't worry if you're off, the challenge rating won't vary significantly).
- If a power makes it easier for the NPC to land a hit, add to their Attack Bonus Modifier. (If the NPC can be granted Advantage on attack rolls frequently you might add +4 to their Attack Bonus Modifier. Some effects the NPC might have which give their opponent advantage on attacks against them might reduce the Attack Bonus Modifier by 4).
- Damage Per Round and the Damage Per Round Modifier can be used interchangebly or in unison, as they do not appear on the NPC Stat block; but the Damage Per Round segment has a quick and dirty calculator if you need it.
If you would like help deciding or would like some suggestions, please come to my (Troy Monteith) channel in Rob Twohy's discord server, where you are likely to find others who are more than willing to help. https://discord.gg/8T3cZJH.