The toilet is clogged.

1. Clean the bowl. This may mean that you have to flush a few times or you may need to plunge.
   
   
2. Note: If you're having trouble (e.g. if the toilet is clogged) you may need to consult a plumber.
   
   
3. Open the supply valve fully.
   
   
4. Remove lid from tank. 
   
   
5. Make sure the refill tube is connected from the water control and inserted into the overflow tube without being kinked or damaged.
   
   
6. Adjust the water level.
   
   
7. Take 3 arms length of toilet paper and put it on water spot.
   
   
8. Flush
   
   
9. Does it work?