Ambleside Online school day, begin with the weekly schedule for the year you're using. Look at the list of readings for the week from the Ambleside weekly schedule, plus your list of other work you want to do each week (which is mostly listed on the weekly schedule--nature study, math, phonics/reading, etc.).
What needs to be done on any particular day is 1) all the daily work (math, poetry, etc.), 2) some number of reading assignments (I usually take the number scheduled for the week and divide by the number of days we'll be schooling to figure out how many to read each day; if a reading is particularly long or difficult it counts as two), 3) some number of other assignments that happen at least once a week but not every day (nature study, artist study, etc.).
I school my new student during nap time so that I can focus my attention on the student. (My older dd doesn't need this focus, so she schools throughout the day with lots of breaks in between because she prefers that.) Year 1 takes about 1-1/2 hours each day, perhaps 2 hours, if you remember to keep each lesson short and move efficiently from one to another. I let my student choose the order of the work (but not how much work is done), although I provide some guidance so that we move from one type of activity to a different type of activity.
The work we do comes straight from the weekly schedule. Daily items happen daily. Items that occur more than once a week but less than daily need to be balanced so we don't end up doing all of them in one day, but I have them on my list and cross them off as we do them so I can easily see how many we have left to do. We do as many of the weekly items as we need to each day to stay on track for the week.
Some subjects we don't cover during this official school time. For instance, composer we listen to during supper. Hymn we listen/sing at breakfast. Folk song is covered at lunch.