These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.
— 1 John 5:13 —
If you were to ask a rabbi, "what comes after death?" Most of them won't have an answer. Even though the Jews gave us the Bible, they don't know about the “afterlife”. We weren't really told about it until Jesus came. There is only one version of what happens after we die which is the truth. His name is Jesus. Jesus means savior. Jesus said, “I am the way, the truth, and the life. No one comes to the Father but by me." Reincarnation isn't a thing. It doesn't happen. How do I know? Jesus is the truth.
Our bodies need a few things to sustain life: food, water, and air. We can live a little while if we get those things, but without clothing and shelter the elements will kill us pretty soon. Even if we maintain all of these things, death is just around the corner. Physical life is fleeting. None of these things can give us eternal life. Jesus is the bread of life that came down from heaven. He is the only way to eternal life, and that is the truth. How do I know? I know it by faith.
Hebrews 11:1 Now faith is the substance of things hoped for, the evidence of things not seen.
Faith isn't wishful thinking. It is just like instinct or intuition. I'm sure you believe in those things. Some things you just know, without knowing how you know. Faith is more like instinct. Instinct is a built-in or programmed knowledge. Faith is a gift from God.
Hebrews 11:6 But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.
Ephesians 2:8 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Faith comes from God. You can not “work it up." It isn't the "power of positive thinking". But you can ask for it. Even if you don't believe in God, He sees you and hears you. You can ask Him in prayer, “God, if You exist, show me the truth.” If you sincerely want to know, He will know, and He will answer that prayer. If you are not sincere, He will know, but He may still answer that prayer, or He may not.
I can tell you the rest of the story about life after death, but if you don't sincerely want to know, it becomes casting pearls before swine. This isn't meant to be an insult. This isn't something you can "figure out." This is something you need God to show you.