Under UserDSN, select a database and then select Configure.
Name = Database name ie LOM2Account, Description = blank, server name as XYZ-PC\SQLEXPRESS or similar.
Have the ODBC set to work with SQL authentication like the main database and tick the tickbox for connect to SQL. Enter the ID and pw in the fields then click next. (You could also deselect the tickbox then carry on to the end and test the datasource.)
Change the default database should be ticked and the relevant database selected. Click next then click finish.
Click Test Datasource.