Laravel - Get/generate form value based on the multiple drop down selection

I want to generate a specific form value based on the selection of different table and that value also should be the combination of the drop drown list values.

Drop down list in the form

Week table - week 1, week 2
Date table - 01.01.2020, 02.01.2020
Day table - Thursday, Friday
Slot table - 10am-11am, 11am-12pm

Specific form - Text input value from the following selection

For example - the value should be On the selection of week 1 from week table + 01.01.2020 from Date table + Thursday from Day table + 10am-11am from slot table

And the output value must be combination of the selected and output must be **

week1_01.01.2020_Thursdsy_10am-11am

via Chebli Mohamed