|Picture from historyhub.ie|
The drafting of Bunreacht na hÉireann was supervised by de Valera himself. The document was a clean slate - the old Free State constitution had been changed so much by de Valera that a new version was needed anyway, but he also wished to give the institutions of Irish democracy a more Gaelic Irish feel - so the President of the Executive Council became the Taoiseach, for example.
Throughout the drafting process, de Valera consulted with Fr. John Charles McQuaid (the future Archbishop of Dublin), ensuring a Catholic influence on the document. However, de Valera stopped short of making the Catholic Church the official state religion.
Bunreacht na hÉireann was put to a plebiscite (a special kind of referendum) and was approved by the people of Ireland in June 1937. It was enacted six months later and has been in place since.
If you are interested in writing your project on the drafting of Bunreacht na hÉireann, UCC historians Dermot Keogh and Andrew McCarthy have a weighty book on the subject entitled The Making of the Irish Constitution. However, books concerning de Valera, McQuaid and Irish society and history in general in the early 20th century will also be of great use.