with this code you can create a database:
...
using FirebirdSql.Data.Firebird;
...
FbConnectionStringBuilder builder = new FbConnectionStringBuilder();
builder.DataSource = "COMPUTER_WITH_DATABASE";
builder.UserID = "SYSDBA";
builder.Password = "m*******y";
builder.Database = @"c:\database.fdb";
builder.ServerType = FbServerType.Default;
FbConnection.CreateDatabase(builder.ConnectionString);