Marina,
Ad Totam Ecclesiam was a directory (I believe formally titled, in English,
The Ecumenical Directory). It was issued by the The Secretariate for Promoting Christian Unity in 1967, as an outgrowth of the Decree on Ecumenism that resulted from Vatican II. It was re-issued (with relatively minor revisions as my memory serves) in the early 1970s. I doubt that you will find either of those versions on line in English, although you can likely find some excerpts.
The current document, which is the legitimate successor of the earlier editions, is titled
The Directory for the Application of the Principles and Norms on Ecumenism. It was issued in 1993. The need for the 1993 revision cited the intervening issuance of the Codes of Canon Law - Western (1983) and Eastern (1990) and the Catechism of the Catholic Church (? 1992).
It’s been so long since I’ve read the original text that I can’t comment meaningfully to the extent of differences between the editions.
Many years,
Neil