You can directly add the meals/recipes on your meal plan to the Food and Exercise tracker from your meal plan.
To do so, go to your meal plan in Food > Meal Plan. You will see your plan like below:
If you wanted to add everything that is on your plan for that day, you can click the ticks under each meal.
Once you press the tick, you can ensure you have the correct date to track it to (can change with the arrows <>), and ensure you have the correct time of day selected.
Then select "done" and it will be added to the Food and Exercise Tracker.