How to show the calendar months in several rows ?

Please note, since version update 4.2 of the Booking Calendar, this feature is possible to configure directly in the booking shortcode in “option” parameter. Please check how todo this here

If you want to show the calendar months in several rows, so then you can make this configuration.
For example, If you want to show months in 2 columns, maximum 2 months per row, so then you can make this customization:
Please open this file: ../wp-content/plugins/booking/css/client.css
at line 236
find this code:

.datepick-inline {
  margin-bottom: 10px;
}

and replace it to this:
.datepick-inline {
  margin-bottom: 10px;
  width: 575px ! important;
}

If you want to have other number of month rows, please change the width to other value.