The following is from Fr. Don Calloways website: https://consecrationtostjoseph.org/introduction.html
What does it mean to consecrate yourself to St. Joseph?
What does it mean for a person to be consecrated to St. Joseph? Well, it basically means that you acknowledge that he is your spiritual father, and you want to be like him. To show it, you entrust yourself entirely into his paternal care so that he can help you acquire his virtues and become holy. Total consecration to St. Joseph means you make a formal act of filial entrustment to your spiritual father so that he can take care of your spiritual well-being and lead you to God. The person who consecrates himself to St. Joseph wants to be as close to their spiritual father as possible, to the point of resembling him in virtue and holiness. Saint Joseph, in turn, will give those consecrated to him his undivided attention, protection, and guidance.
If you have already consecrated yourself to the Virgin Mary, can you be consecrated to St. Joseph, as well?
The answer is a resounding “Yes!” God desires that all children be committed to the care of a mother and a father. You are not a member of a single-parent spiritual family. Mary is your spiritual mother, and St. Joseph is your spiritual father. The spiritual fatherhood of St. Joseph is extremely important for your spiritual growth. Total consecration to Mary is not diminished by total consecration to St. Joseph. Mary wants you to consecrate yourself to St. Joseph! Jesus wants you to consecrate yourself to St. Joseph! Everything you have given to Jesus and Mary can also be given to St. Joseph. The hearts of Jesus, Mary, and St. Joseph are one.
Consecration to St. Joseph emulates the tried-and-true preparation method employed by St. Louis de Montfort in his Marian consecration, highlighting many of St. Joseph’s titles, privileges, and heroic virtues.