There is no "right" amount when compiling a to-do list. If it seems overwhelming or redundant, break down bullet points into sub lists for individual tasks. Nothing is ever too minor, nor is it wrong to write down something you have already completed, for the additional sense of achievement.
I would say five, start with a couple easier ones which you can cross off right away and feel accomplished and motivated before tackling the big ones. If the list is too long, it might feel discouraging to look at. If a large task is made up of multiple smaller tasks, break it up and make the smaller tasks part of your todo list, rather than simply the big one. Plan a reward for yourself for completing your todo list.