http://edwardfeser.blogspot.com/2014/05/pre-christian-apologetics.html
This goes over everything leading to the Christian faith by a great philosopher, very insightful and in depth.
But they key things is to go to a Catholic Church and ask to enter the RCIA program and be baptized.
Everything else is a bunch modern novelties that have a history going back at most 1 or 2 hundred years.
If that's not enough prepare to study a ton and not know anything for sure for a couple years.
A measure of the true religion though is reasonable to use, because it isn't realistic for everyone to become a historian and theologian. (however this still logically only comes after establishing the metaphysical and philosophical principles Dr. Feser covers)
If you figure out some of the key principles any potential claim to the true religion has it makes it easy to discount all the obviously false ones.
A key first principle would be first to establish that theology and the truth of theology matters. God is obviously the most important thing, so anything about him has to be of greater importance then the details of anything else. What follows from this is that God cares that whatever his religion is has an accurate view of them, this seems obvious but it's important to make clear.
Any religion that has any potential claim to be true, has to have a system that values the truths of their theology.
There are a couple things we can get from this.
They have to be united theologically (historically and currently). Since theology is just describing truth there can't be multiple contradictory views of it, and it won't change overtime.
That means any claim to Christianity has to have some mechanism ensuring that people hold to the truths that have always been maintained. It doesn't make any sense to say different groups like Unitarians and say Anglicans are in any way the part of the same religion, as they have totally different theology.
This also works within groups, say pentecostals or mormons, they greatly differ in theology not only with other groups but within themselves. This means that pentecostals or mormons don't have any claim to be even possibly a true religion.
God is perfect, loves us, and to give us a false view of him is evil so it's not something his religious would do.
So there has to be among whatever the true religion is Unity historically and currently in theology.
This comes to another issue, any religion with a ton of people will have people with misunderstandings or just likely to come up with stuff on their own. If God is important, he'd want a way so people can correct their misunderstandings and avoid inventing error. This means the true religion has to have in some way an authority to teach truths about God. Theology is complicated, and as I said earlier it just doesn't make any sense to expect everyone to become a theologian and find the true religion, so rather it makes more sense that there would be some sort of teacher established that God assures us we can trust. This way anyone, from the greatest theologian to the simplest peasant could be confident they know the basic Truth's about God.
And as soon as you get to this point nothing but Catholicism is even possible, just from the idea that theology is important we can totally eliminate all other claims of being the true religion, and Christ teaches this as well.
If you want to read something
https://archive.org/details/thechurchofthepa00pracuoft/page/n11
or listen to something
https://www.youtube.com/watch?v=faIB-sOBDKk
https://www.youtube.com/watch?v=xl3pD4l0K5U
These go in depth on it