How to use 'List of thing' Field

Need help
1

I’ve a table ‘Event’ , this table has one ‘list of thing’ field name ‘category’ which is custom type.
category type has 2 fields ‘name’ and description.

now I am trying to make add new record in list of category for existing event. can you suggest some document or example how should I do it.

thanks and regards,
jitesh verma

2

How to Add multiple fields in custom ‘List of things’.