Did you find any instructions for this plugin k5?
I don't even know what the fields look like or where to add/find/edit them.
If I knew how to do it, I would uninstall everything and re-install following a different tutorial.
Custom fields are the main reason I am trying Piwigo and it sounds ideal.

I get an error when I try to add a new custom field, the fields do get added but I never get the option to add them to a photo or display them.
The error is as follows:
Create new custom fields/var/www/photos/piwigo/_data/templates_c/p6jhns^db0e2c8d687818179cac362afeae772b0dcc7135_0.file.admin.tpl.php on line 253

Warning: Attempt to read property "value" on null in /var/www/photos/piwigo/_data/templates_c/p6jhns^db0e2c8d687818179cac362afeae772b0dcc7135_0.file.admin.tpl.php on line 253

Warning: Trying to access array offset on value of type null in /var/www/photos/piwigo/_data/templates_c/p6jhns^db0e2c8d687818179cac362afeae772b0dcc7135_0.file.admin.tpl.php on line 253
">
Wording

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Environment
Piwigo 13.7.0 Check for upgrade
Installed on 25 June 2023, 5 days ago
Operating system: Linux
PHP: 8.1.2-1ubuntu2.11 (Show info) [2023-07-01 12:58:40]
MySQL: 8.0.33-0ubuntu0.22.04.2 [2023-07-01 12:58:40]
Graphics Library: GD 2.3.0
Cache size 502.95 MB   calculated right now Refresh
Activated plugin list1
User Custom Fields