Auto populate Name column Document Set with selected value lookup column

According to below question and pictures I am looking for a way to Auto populate Name column Document Set with selected value lookup column But I do not know how to do that.

actually i wanted hide Name column on Document Set but i read some where is impossible.

also i tried with java script but i could not.

actually i do not know how?

https://sharepoint.stackexchange.com/questions/286966/auto-populate-name-field-with-value-from-a-lookup-column-on-new-document-set-for