This article will help you with the new Pinning item, Bookmarking and Project Filter features added to Projects in Powered Now
The pin feature allows you to select items within a project and puts them to the top of the project timeline when you select the pin icon attached to the item
Timeline filter allows you to search specific items within a projects i.e. documents, notes, etc. When clicking on 'Filter Timeline' you will have a dropdown where you can select the type of item you want to look up within that project.
You can now add a Bookmark to your items within your projects as a reminder to go back to items you need to go back to in a future date. To do this turn on the Bookmark icon attached to the item you need to go back to then when you come back to the project you can use the 'Filter Timeline' to look up your marked items within the project.