How to get team users from a team getting it from input

i'm trying to build my first WorkFlow that take from input a Team and get all the users inside this team and put them into the "TO" field of a CRM Email.

My first Challenge is retrieve input Classes compatible. For example the classes: XrmDataContext, TeamMembership, Email(email.Subject) the compiler don't recognizer them.

I've been trying whit this code I've found on internet, but is not so clear for me.

    [Input("Team Name")]
    [Default("Case Team")]
    public InArgument<string> CaseTeam { get; set; }

    [Output("Date time")]
    public OutArgument<DateTime> TaskDueDate { get; set; }
      protected override void Execute(CodeActivityContext executionContext)
    {
        try
        {
            // Create the tracing service
            ITracingService tracingService = executionContext.GetExtension<ITracingService>();

            // Create the context
            IWorkflowContext context = executionContext.GetExtension<IWorkflowContext>();

            IOrganizationServiceFactory serviceFactory = executionContext.GetExtension<IOrganizationServiceFactory>();

            // Create the Organiztion service
            IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId);

            // Get the target entity from the context
            Entity target = (Entity)context.InputParameters["Target"];

            // Prepare DataContext by using AutoGenerated cs file
            XrmDataContext datacontext = new XrmDataContext(service);

            // Get the Team Name from the Workflow input parameter
            string teamName = CaseTeam.Get<string>(executionContext);

            // Get the Team Id from the Team Name
            var team = (from t in datacontext.TeamSet
                        where t.Name == teamName
                        select new { t.TeamId }).First();

            // Get all the members of the team to send email
            List<Entity> teamMembers = (from t in datacontext.TeamMembershipSet
                                                where t.TeamId == team.TeamId
                                                select t).ToList();

            // Send email to memebers of the team
            CreateEmail(service, teamMembers, target, context.InitiatingUserId);

            // Set the Task DueDate to 2 days by using Output Parameter
            TaskDueDate.Set(executionContext, DateTime.Now.AddDays(2));

        }
        catch (SoapException ex)
        {
            // Add the SoapException message in event log
            EventLog.WriteEntry("code error", "Error occured in " + ex.Detail.InnerText.ToString(), EventLogEntryType.Error);
        }
        catch (Exception exe)
        {
            // Add the GeneralException message in event log
            EventLog.WriteEntry("code error", "Error occured in " + exe.InnerException.ToString(), EventLogEntryType.Error);
        }
    }

    public static void CreateEmail(IOrganizationService service, List<Entity> teamMembers, Entity caseEntity, Guid loggedinUser)
    {
        // Create Email 
        Entity email = new Entity("email");

        // Set the from user of the email to Logged in user
        Entity fromParty = new Entity("activityparty"); 
        fromParty.Id = new EntityReference(SystemUser.EntityLogicalName, loggedinUser);

        List<Entity> toPartyList = new List<Entity>();

        // Add the Activity party for each member in the team
        foreach (TeamMembership user in teamMembers)
        {
            ActivityParty toParty = new ActivityParty();
            toParty.PartyId = new EntityReference(SystemUser.EntityLogicalName, user.SystemUserId.Value);
            toPartyList.Add(toParty);
        }

        // Add the subject and description by concating the case ticket number
        email.Attributes.Add("Case " + caseEntity.Attributes["ticketnumber"].ToString() + " Added. Please review");
        email.Description = "Case " + caseEntity.Attributes["ticketnumber"].ToString() + " Added. Please review";

        // Add To and From users to email
        email.To = toPartyList.ToArray();
        email.From = new[] { fromParty };

        // Set the case regarding
        email.RegardingObjectId = new EntityReference(Incident.EntityLogicalName, caseEntity.Id);

        // Create email
        Guid emailId = service.Create(email);

        SendEmailRequest sendRequest = new SendEmailRequest();
        sendRequest.EmailId = emailId;
        sendRequest.TrackingToken = string.Empty;
        sendRequest.IssueSend = true;

        // Send the email message.
        service.Execute(sendRequest);
    }