The bride and groom must submit a marriage notice to the registrar for the district where the marriage is to take place at least four weeks before the date of the wedding. If the bride or groom has previously been married, they must submit a marriage notice to the registrar at least six weeks before the date of the wedding. 

When you visit the registrar you must take with you your birth certificate. If either of you were married previously, you should also take with you your divorce certificate. If you are a widow, or widower, the death certificate of your former spouse will be required also. (Please note that an appointment should be made with the registrar to submit the forms as well as collect the schedule)

The registrar will prepare a marriage schedule, which is necessary for the wedding to take place. The bride or groom must collect the marriage schedule during the week in which their marriage takes place.

Witnesses to the marriage (i.e. the best man, chief bridesmaid) must be sixteen years of age or over.

The wedding cannot take place without the marriage schedule. This must be presented to the minister prior to the wedding ceremony beginning.

The following link will take you to the General Register Office for Scotland and offers more information about a marriage schedule.

https://www.nrscotland.gov.uk/registration/i-want-to-get-married-in-scotland-how-do-i-go-about-it