Here are some ideas Cynthia.
I'm not much help in this department, but I love the idea! Would you want to make the closet connect with your room, or are you planning to leave the existing doorway?
Do you have a picture of the space?
A friend of mine did this. She is not a blogger so I don't have a picture but she added closet organizer shelving some with rods and some with shelving around the walls then added dressers and a bench in the middle of the room. They love it.
I added wall to wall shelving unit I purchased at one of the box stores made for clothing. Simple to install. You can add shelving units for sweaters and shoes.
Wow, that'll be nice! You can buy closet systems or shelving, racks, shoe storage, and hanging poles. Evaluate what you plan to put in there and that should dictate what you need to install.
Just remember this will bring down the value of the home minus a bedroom unless you make it reversible if you ever plan to sell.
We made over my walk in closet very easily which would apply to your bedroom too! https://www.aratariathome.com/blog/weekend-closet-makeover