Here’s something I wrote to try to explain Paul’s Gospel as simply as I could, but while covering all the bases. Feel free to use it for explaining it to others yourselves, although you might want to edit the last paragraph where I talk about my eBook if you do want to include that link. Here it is (if I add anything to it or edit it, I’ll do my best to remember to edit it here too):
The Gospel of Paul is simply that Christ died for our sins, that He was entombed (He was entombed, not just His body while He went elsewhere, which means He actually died), and that He was roused the third day. Because of this, sin has already been dealt with for every human who ever lived, and every one of them will eventually experience salvation (which means to be resurrected if dead, and to be made immortal and sinless; it has nothing to do with avoiding a mythical torture chamber called “hell”), but each in their own order: first the body of Christ at the Snatching Away, then the resurrected members of the Israel of God after Jesus returns to earth, then everyone else at the end of the eons. And if God has elected to give you the faith to believe this Good News now, it means you’ve been chosen to join the body of Christ and you’ll be one of the first to enjoy salvation. But even if God hasn’t chosen to give someone the faith to believe this Good News, Paul promises us that everyone will eventually experience salvation whether they believe the Good News now or not, and so, while those who outright reject this Good News might miss out on getting to live in the kingdom of God during the next eon or two, you ultimately don’t have to worry since even they’ll eventually enjoy salvation, so you can be conciliated to God (be at peace with God in your mind) because God was in Christ conciliating the world to Himself, not reckoning their offences to them.
If you’d like to learn more about what Scripture really teaches about salvation (including the scriptural references for what I wrote above), I wrote about it in the first four chapters of my eBook, which is available for free here on my website.