Daily Workout Journal - How Do I Make A Daily Journal?

I’m trying to make a workout/fitness journal that would track calories and such along with your daily workout and apparently this is harder than it sounds…
i’ve read one daily journal thing, downloaded the example he gave and it’s just not what I’m looking for… I think.

I WANT to just type in your workout/calories (using text inputs) and have it save to a variable under a date… then I can load everything under that Variable Date and display it in 1 text (calories,protein,fats + your workout of the day) so the user can see what they ate/what workout they did on what day.
I’ve tried the ‘for every child in X place it into X at child X’ but it doesn’t seem to place the child correctly, it inserts it instead of appends… and when I try append it just says [array]
any examples of something like this out there I could look at? I’ve tried and read everything I can and haven’t had any luck. im currently smart enough to know I’m too dumb to do this, or I’m overthinking it.

or is this even possible? please help.

Text Inputs (foods, workouts) go into the Days Journal, which holds your Daily Info (array?) and have that Days Journal array with your Daily Info go into a new structure/array of Dates that hold all of the Days Journals under the key of Date…?