One of the directions that Jesus gave to the disciples before ascending to the Father was that they were to return to Jerusalem and wait, and they would receive power from on high. The returned to Jerusalem, to the Upper Room (also called the Cenacle), and began nine days of prayer and waiting. In the Upper Room with them was Mary, the Mother of Jesus, and the Mother of the Church.
This began the first novena by the Church. A novena is nine days of prayer dedicated to some specific devotion or intention. There are many novenas in the spiritual arsenal of the Church. But this is the first, and the one on which the others are based.
The Novena to the Holy Spirit is made up of prayers and reflections, which are done for nine days in a row, beginning with Friday, May 22, the day after the traditional celebration of Ascension Thursday, and going until Saturday, May 29, the day before Pentecost Sunday.
There is no one set of prayers for this novena, but I am recommending the prayers on www.companionscross.org. You can find others on the internet, or you can make up your own set of prayers and reflections.