To destroy all the jelly on level 123 your required to play in the top 1/3rd of the grid at first. The best way to open up the rest of the board is to try and position 2 special candies next to the bricks as show in the image. If you can accomplish this then the board quickly opens up. After doing this try and remove the chocolate on the side that you have opened quickly. Doing this should mean that one entire half of the board is open and this greatly helps you to begin creating special candies to go on to remove the jelly.