You have all that lovely information you've researched. You have created a new world with many customs. How do you inform the reader of the things you think they should know. Turning your story into a non-fiction discussion isn't the way to go but there are some ways to show and tell your reader about these unique and interesting things.
The first way to do this is build it into your scene. Find a way to have the characters show the information in a subtle way. Remember when you create a scene, you are doing several things. You are showing the characters with their assets and faults. You are advancing the plot and letting the reader know about the background facts including the setting.
A second way isn't as easily done and that's to put a writer intrusion passage between a scenes. Remember, there needs to be a lead in to this material and an exit that fits the story. A much harder way and keeping the reader's interest could be difficult.
The third way is to let the characters do the reveal. A dialogue between two or more characters, but try not to be disgorgin information all of the participants know. This could turn the reader off with thoughts like they already know that. Using a character's inner dialogue is a way of letting a character let you know what's been happening in the past or to allow a bit of that research to enter the story.
So build in the information you need is important but make sure you just don't want to give the reader a history lesson, a primer on methodsof death or how your world came about.