know what sections you want to include, create an index to add the collections there. you can add to the index as you go developing your bullet journal later on too.
the index is going to take up the first two pages in your bullet journal so leave them free when adding your collections.
when putting the journal together, space out the sections so that you have a good number of pages for each.
then choose where they will be located and write down the page number. once all of this is done, you can then use the information to create your index.
this is another area that you can keep working on and 