The Steps to be Taken to Convert to the True Catholic Faith
The first step is to try to contact the Catholic priest (Sedevacantist) closest to you and find a Mass Center. I recommend you to search in the directory Lux Vera Directory or in the directory of Father Héctor Lázaro Romero published in his blog "Revista Integrismo".
The true Catholic is obliged, under penalty of grave mortal sin, to refuse to attend any Mass offered in union with Bergoglio and its hierarchy, because he is the head of a false religion, and by attending a Mass offered in union with Jorge Mario Bergoglio makes you inevitably in union with him and his false Church and therefore in schism. It is incredibly dangerous to entrust your soul to a priest who professes that the head of a false religion is the Vicar of Christ on earth.
The next step is to read a traditional catechism, preferably with the help of a priest, but otherwise you can do it alone. I recommend the Catechism of St. Pius X to begin with and the Catechism of Trent to deepen further, you must make the Profession of Faith of the Council of Trent.
If you have not been baptized you should look for a Catholic priest to baptize you and if you have no priest near your location and you also do not have the possibility to travel to look for another priest who can baptize you, you cannot be baptized by a lay person except in danger of death, in case of danger of death look for a truly Catholic friend to baptize you or else someone who can do it with the right intention, see in this case this article.
If you have been baptized by a priest of the false Church of Vatican II, and there is no eyewitness that your baptism was done correctly, you would need to make a general confession and receive conditional baptism. If you have been baptized in a Protestant sect, you would need to do the same. Baptisms granted by Eastern schismatics are valid, unless they were granted by a priest under the patriarchate of Russia, in which case an eyewitness is needed. If you were a member of any false religion, you must reject it after making the Profession of Faith of the Council of Trent.
As a member of the Mystical Body of Christ, he is obliged to assent to all that the Church teaches; he must maintain that the Second Vatican Council and its teachings and those of the Popes after Pius XII are false and heretical, and must accept as a certain theological conclusion, that Jorge Mario Bergoglio is not the Pope; he does not have the Authority of Christ to teach, rule and sanctify the faithful because he is a heretic.
As a layman, this is all he has to do. If circumstances dictate that you have to defend Catholicism, that is, sedevacantism, I recommend you to visit Novus Ordo Watch and True Restoration and Traditional Latin Mass Resources.