Hi there!
Here is a toddler's bedroom that doubles up as a playroom. It has a bed, surfaces, toys, the big doll house, seating, and enough room on the walls to add your own art.
8x5, 6,787 Simoleons.
All items are base game, no CC used.
To add a room to your lot, navigate to your Tray folder, usually found in Documents>Electronic Arts>The Sims 4>Tray and unzip the file into it or unzip in downloads and move the files into Tray.