The program is all about food groups:
As the program is based on food groups, when making substitutes you just need to ensure that you replace with a food from the same food group, and that you have the equivalent amount.
There is a vegetable you do not like (broccoli) that you want to substitute out.
Note the amount of broccoli in vegetable units, if you have 1 unit worth of broccoli (135g) that you want to replace, you just need to ensure you swap with another vegetable e.g. cauliflower, and that you have the equivalent amount (1 vegetable unit).
Finding the equivalent amount to use, you can then search for cauliflower in the food & exercise tracker to find out just how much equals 1 unit. Then just eat that amount of cauliflower instead of broccoli and that is all you need to do, as long as you are having the same amount of units.
Above 1 unit of broccoli.
Search for cauliflower and adjust to find the equivalent amount of 1 unit (180g).