It is similar to joining the LDS church except the interviewer is the Lord and he employs no servants there.(2 Ne. 9:41) You have to make covenants and commitments prior to joining and you have to learn a few things like how to talk to God and hear His response. It can be hard to join for some or it can happen quickly for others based on how well they have already prepared before they decide they are going to join. Seek and ye shall find. Knock and it shall be opened to you.
1) we have to be “just”. (D&C 76:50)
2) we have to be washed and cleansed from all sin and receive the Holy Spirit. (D&C 76:52)
3) we have to be overcome by faith, sealed by the Holy Spirit of Promise (Holy Ghost, Acts 2:33) and we have to be just and true. (D&C 76:53)
4) once we qualify as described above then we are among the church of the firstborn, thus, we cannot arbitrarily join it.