First of all, Church could simply be seen as a gathering of followers of CHRIST for good.... It exists more like how Garden exists. Firstly, seeds are sown in the garden where they are nourished and feed with foods/water to germinate and grow from childhood to adulthood and then begin to produce good fruits/foods for people and animals to consume. That is more like how the Church functions.. , The main purpose of a True Church is to convert new people, have them buried/baptised in water and raised from the dead to become a new human... like seed are first buried in the ground and raised to become a plant. In other words, the old you dies and your new you spring up to become a new person and member of a Church... like how plant grows from seed to become part of a garden.
Once you become a young plant it is assume you are a child in the Church and you are constantly nourish, nurtured, feed with the Word of GOD to grow into maturity and start producing good fruits for the benefit of others. To produce good fruit is to be doing good (your "good" has to be according to GOD's Two Greatest Commandments/Law), and being beneficial to others with the goods. At the matured stage you should be qualified to convert people into the Church and feed them with the Word of GOD to adulthood/maturity.
This should help you understand the purpose of a Church and also help you know what qualifies you or others as a Church members. Once you are baptized, you become a Christian (or a follower of CHRIST) and part of the Church. Make sure you are fed with the Word of GOD always after baptism, followship with other Christians (whether they are your biological family or outside of the family). By the way, your Church Members are also part of your family but make sure they do good always to qualify as your True Family members else when you mingle with them at a vulnerable/young stage, you become corrupted.
Becareful attending the worldly so-called churches. You will know them by their fruits. Every follower of CHRIST is your Church member no matter where they are. Their Teachings/doctrine & beliefs will be thesame as yours assuming your beliefs/doctrine is built on a solid foundation "the Word of GOD". If it's not built on a solid foundation, then you can rightly predict that the so called church will crumble when exposed to high quality test. Flee from such so you don't crumble with them. Everything a follower of CHRIST do should be based on the Word of GOD otherwise during time of testing or adversity he and others like him will crumble.
The Word of GOD is JESUS CHRIST and HE is the Way, The Truth and Life. Read the Word of GOD below, you will begin to transform into a new person as the Word is sown in your heart. Listen and believe and CHRIST will form in you and you will grow with HIM to maturity, as One.
Feed on The Word Of GOD by Listening to GOD's Words Here: Complete Bible in Audio format: (King James Version and New Living Translation):
*AudioBible, KJV (better to start from Matthew to Revelation as a beginner)
https://m.youtube.com/playlist?list=PLIxhnx0kb33ORn8RQgHH54rdJMmqaRfmd*AudioBible, NLT ((better to start from Matthew to Revelation as a beginner)
https://m.youtube.com/playlist?list=PLHZp_z2RSv22NTf-Mqsfj9adjWMtuMSIe