Add – sign in value on specefic place Power bi/Power query

I have a column in PowerBi namend X-rates. The value in the column is for example X00360. I want to change that value to X-00360. So after the X i need "-" sign.

In Excel i used iferror(CONCATENATE(left(O2;1));"-";right(O2;lenght(O2)-1));"")
but how to do this in powerquery?

X-rates (current) X-ratesNew (expected)
 X00360            X-00360

>Solution :

Add a new column and type in

Text.Start([#"X-rates (current) "],1) & "-" & Text.Middle([#"X-rates (current) "], 1)