You can put the Reservation form on any record page, and use it to create Reservations without needing to navigate to the calendar. The underlying Booker25 conflict checking technology will make sure that any related record you book is actually available for the Start and End DateTime that you filled in, if you configured Dimensions with Intelligent lookups.
Configuration
Add the standalone Reservation Form to a record page
Edit the record page to which you want to add the standalone Reservation
Select the Standalone reservation form component and drag it anywhere on your Lightning page
Make the standalone Reservation Form available on mobile
You can make the standalone Reservation Form available on mobile by adding it to a Lightning App page. This Trailhead explains how to do this. You can specify the name of a flow that will run before loading the reservation form. This allows you to prefill data in the form if needed, such as the recordId in a dimension field.