Open Skyrim.ini in Documents/My Games/Skyrim or Documents/My Games/Skyrim Special Edition
note: location of Skyrim.ini can vary. If using MO2, your Skyrim.ini location might be Users%user%\AppData\Local\ModOrganizer\Skyrim Special Edition\profiles\Default
Look for the [Papyrus] section and edit as follows, or add the section and/or line if not already there
[Papyrus]
fPostLoadUpdateTimeMS=2000.0
bEnableLogging=1
bEnableTrace=1
bLoadDebugInformation=1
Afterward, in that same folder, you will see a new folder called Logs. Inside that is the Script folder. Inside Script you will (eventually) find 4 logs. Papyrus.0.log is the most recent. When you share the papyrus log in the Support Forum, please provide it as an attached file, or use Pastebin and link your pastebin.
If using Pastebin, no need to signup... just open your papyrus log in notepad... copy... paste into Pastebin... click create new paste button... share the URL it's created up top