Indoor bonsai should be kept around room temperature at all times. Ensure the tree is placed near an area with plenty of sunlight throughout the day.
Watering
Place your bonsai tree in the center of your watering tray and fill the tray with water until the water level can touch the openings at the bottom of the pot. Check how much water is in the tray every day and refill as necessary. If the tree is not getting sufficient water the rocks on top will appear light in color and the tree will feel much lighter. In the addition, soak it in the sink or container half way of the pot for 1-2 hour once a week, large tree may be overnight.
Fertilzing
Use liquid bonsai fertilizer. Follow the instructions that come with your chosen fertilizer. As a general idea you may want to fertilize once every month.
Trimming/Repotting
See the Workshop for details and demonstrations, or online.