From your 'My Hub' page (please see below)
On the left hand side of your account, you will see the side menu in which you can select 'Nutrition'.
You will see a list of any nutrition plans you have created
You can then select the nutrition plan that you would like to add the meal to and then scroll to the bottom of the page and select the button 'Add Meal'
Once you have selected this button, it will then appear with the list of meals that you had created, so you can then select the correct one to add to the plan
When the meal has been added, it will show on the nutrition plan and you can then press 'Save Plan' and the client can then go through and log this