Make your emoji variable. Use the variables x and yfor the center of your emoji and use + and - to position the elements relative to the center of it. So if you change one of the values in x or y, your emoji should change the position.
If you like, you can have a look at the example in this video where you can see how I use variables to make it more easy to change the position of the emoji.
Additional exercise
Make the size of your emoji variable as well. Use a variable s for a scale value. If the value is 1.0 your emoji should have the full size (100%). If the value is 0.5 it should half of the size (50%) and so on. Note that we cannot use the name scale for the variable because it is already in use by p5.js.
You can see a sample solution in the following video.