Like its mobile counterpart, it gives you access to flights, hotels, tour packages and other relevant information in one place. The left-hand menu has tabs that give you access to each of those details. If you're signed into your Google account, it can also give you trip suggestions based on your location and previous searches. Also, it can keep track of all the places and flights you've saved, so you can go back to where you left off.
Once you've already booked hotels and flights, it will automatically add the information to your timelines, so long as you've received an email confirming the bookings. The portal will also keep a record of the hotels and the activities you've looked at and saved in the near future. If you feel uncomfortable giving Google that much information about your trip, though, you can opt out by changing your "private results" and "web & app activity" settings.
In addition to the new portal, Google has also rolled out an update for Maps to highlight popular neighborhoods in the place you're visiting by describing what they're know for. In the coming months, Google will make your hotel and restaurant reservations accessible from Maps, as well.