Good morning
I'm newbie in excel and search for how to remove text after comma and found this formula

=LEFT(A1, FIND(",",A1)-1)

=if(iserror(find(",",d6,1)),d6,left(d6,find(",",d6,1)-1))

I don't understand where to put these functions?

I have 1 column (A) with 20+K list of text
i want to remove all text after "," comma
like these
Émile Zola
Émile Zola, La Faute de l'abbĂ© Mouret
Émile Zola, Le Docteur Pascal
Émile Zola, The Fortune of the Rougons
Émile Zola, The Masterpiece

so i tried to put these formulas in first cell in the column then enter , nothing happened
so please help how to use these function

thanks