many videos for you to watch https://www.youtube.com/results?search_query=diy+flower+pot+fairy+gardens
Karol...Just find the size pot you want and fill it with things you do want as a filler, even rocks then add a nice layer of dirt. Once you get the dirt as you want...start collecting your fairy garden pieces. You can buy sets or you can can purchase individual items. They have cute ones at Hobby Lobby (some are a little pricey), Big Lots has some sets with a fairy, house, table and chairs. The Dollar Tree has lots of individual items and you can make it as large as you want to begin with or just kinda grow it as you go. There are birdbaths, mail boxes, fences, trees, swings, etc. I found some very small stones in my lower yard and used them as stepping stones to the front door of the fairies house. Your ideas can be endless and I loved playing with my doll house as a little girl so it kinda takes me back to that. Plus I get lots of oohs, and awes from adults and the stories you can tell your grandchildren are never ending. Also makes a great gift for kids who love to play make believe even little boys by adding trucks, tracks and farm animals. Just have fun!
Here's a good tutorial on creating fairy gardens from broken pots: https://balconygardenweb.com/how-to-make-broken-pot-fairy-garden/