It's more like a list.
[MC decides to do xxx which starts the story]
[the final battle between xxx and MC happen
list things that happens in fight]
then you add stuff in between
[MC decides to do xxx which starts the story]
[MC restores this]
[MC travels here]
[the final battle between xxx and MC happen
list things that happens in fight]
then you add conversations you imagine the mc having that are important and need to be added when you start actually writing.
then you add smaller events in each section
then you flesh it out in a first draft ovo
I don't really use a timeline.. o3o