You will probably have to use SQL Server Authentication, and not Windows Authentication. This is because there is not a common Windows domain that both SQL Server and your users will be using, so there is nothing available to allow Windows Authentication to work.
Apart from this, there is nothing particularly special about using SQL Server in a Workgroup.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
When I give food to the poor they call me a saint. When I ask why they are poor they call me a communist - Archbishop Hélder Câmara