When you use a single vernacular writing system for all dialects, you can mark entries or senses to indicate which dialects they represent.
To do this, you insert dialects as list items in the Dialect Labels list. Then, choose these list items in Dialect Labels (Entry) and Dialect Labels (Sense) fields in Lexicon Edit.
However, if you use a writing system for a dominant dialect and want to include lexeme forms that are approximately equivalent in other dialects, you should use different writing systems for each dialect. To distinguish the writing systems you add, choose different regional information.
Collect Words with Dialect Labels
Dialect Labels field overview (Lists)