Now you have two record page view default options. Current view called Grouped View and the New Full View. If you’re transitioning to Lightning Experience, this view is similar to Salesforce Classic.
Steps to enable Full View (Beta) in Lightning
1. From Setup, enter Record Page Settings in the Quick Find box, then select Record Page Settings.
2. Select Full View (Beta)
3. Click Save.
At this point, this will override the setup that you have in place, so if there are instances where you want to keep the Group View you will need to make the adjustments
Alternatively, you can create new Lightning Record Pages using the Default template that Salesforce now offers. Once created you can then assign the Record Page accordingly.
This type of Page Layout will not work with large number of fields and related lists in record page.