I've been saved long ago and gotten baptized. I should be safe, right?
First some context: humans are triparite: body, soul and spirit. When someone is born again, their spirit is indwelled by the Holy Spirit. It is analogous to having a fire lit on the altar of a temple.
If someone ever believed in their heart that Jesus Christ died on the cross for their sins and resurrected on the 3rd day, then they were born again in the spirit.
The newly-minted Christian is now a babe in Christ, so to speak, and now part of the Body of Christ, what is known as the
ekklesia in Greek, which is often translated as "church" but it is actually spiritual.
There is a longer conversation about the indwelling of the Holy Spirit, and the manifestation of the FRUIT (singular) of the spirit. See Galatians 5.
There is also a longer conversation about saving one's soul, finding one's God-given purpose, and using time, talent and treasure to fulfill it.
The internet, powered by free speech, has a vast number of sites. Some of them are operated by charlatans so indeed not an easy task to find the truth, but it is out there.
As an aside, I don't believe you have to be a member of a church, nor do I believe you need to confess sins to anyone but God himself.
I also believe that the Biblical tithe ended with the Levitical priesthood which ended in 70 AD. Christians are instructed to be charitable, which is discretionary, and can be more or less than 10%.
Personally, I repudiate all that I have every day. I do my best to be an effective steward of the resources with which I have been entrusted.