I got a slow cooker for Christmas. What is the first recipe I should try in it? Thank you!!!

I myself do not own a slow cooker, but my friends who do own one say that the recipe they use most often is the recipe for chicken marbella from The Silver Palate Cookbook. Apparently they throw everything in and let the cooker do the work! http://www.silverpalate.com/recipe/store-favorites/chicken-marbella
There are versions of slow cooker marbella online.

I would try some dishes you're familiar with- maybe pot roast or a stew, but something you're used to making- for comparison purposes.

I make this at least once a month. Sometimes I serve it as it says in the recipe, but I love to use the broth to make rice and serve the chicken on the side with a green veg.
https://food52.com/recipes/32597-whole-slow-cooker-poached-chicken

https://food52.com/recipes/29740-slow-cooker-barbecue-pulled-pork-with-mango-salsa.
Delicious even if you don't feel like making the mango salsa to go with it.

Soup! Chili! Pot roast (if you're a carnivore)! After ignoring my slow cooker for years, I dragged it out of the cupboard a couple months ago and fell in love with it all over again. Yesterday I used it to make the most amazing Hoppin' John with brown crowder beans, ham bone, and collards.

This is my all time favorite: http://smittenkitchen.com/blog/2010/01/black-bean-soup-toasted-cumin-seed-crema/