OET interlinear HERO (JDG) 21:21

uW Translation Notes:

Note 1 topic: grammar-connect-condition-fact

אִם־יֵ֨צְא֥וּ בְנוֹת־שִׁילוֹ֮ לָ⁠ח֣וּל בַּ⁠מְּחֹלוֹת֒

if come_out daughters_of (Some words not found in UHB: and,you(pl)_will_see and=see/lo/see! if come_out daughters_of Shiloh to,dance with,dancing(s) and,you(pl)_will_go_out from/more_than the,vineyards and,you(pl)_will_seize to/for=you(pl) (a)_man his/its=wife/woman from,the_daughters_of Shiloh and,you(pl)_will_go earth/land Binyāmīn )

The elders are speaking as if this were a hypothetical possibility, but they know that this is going to happen. If your language does not state something as a condition if it is certain or true, then you could translate this as a confident statement. Alternate translation: [when the daughters of Shiloh come out to dance in the dances]

Note 2 topic: figures-of-speech / metaphor

בְנוֹת־שִׁילוֹ֮

daughters_of (Some words not found in UHB: and,you(pl)_will_see and=see/lo/see! if come_out daughters_of Shiloh to,dance with,dancing(s) and,you(pl)_will_go_out from/more_than the,vineyards and,you(pl)_will_seize to/for=you(pl) (a)_man his/its=wife/woman from,the_daughters_of Shiloh and,you(pl)_will_go earth/land Binyāmīn )

The elders are speaking of these young women as if they were the daughters of the city itself. If it would be clearer in your language, you could state the meaning plainly. Alternate translation: [the young women who live in Shiloh]

Note 3 topic: figures-of-speech / explicitinfo

לָ⁠ח֣וּל בַּ⁠מְּחֹלוֹת֒

to,dance (Some words not found in UHB: and,you(pl)_will_see and=see/lo/see! if come_out daughters_of Shiloh to,dance with,dancing(s) and,you(pl)_will_go_out from/more_than the,vineyards and,you(pl)_will_seize to/for=you(pl) (a)_man his/its=wife/woman from,the_daughters_of Shiloh and,you(pl)_will_go earth/land Binyāmīn )

It might seem that the expression to dance in the dances contains extra information that would be unnatural to express in your language. If so, you can shorten it as in the UST.