I managed to work it out, the code looks like this:

Sub Gantt_Chart()

RiSoftGantt.Show


    'Define the variables.
    Dim ValueAxisMinValue As Date
    Dim Title As String, aChart As Chart
    'Store the location of the data as a string.
    

    'Store the start date for the chart.
    ValueAxisMinValue = Sheets("Schema").Range("B3").Value
    'Ask user for the Chart title.
    Title = InputBox("Ange titeln på schemat")
    If Title = vbNullString Then
    Exit Sub
    End If
    'Store the sheet name.
    'shtname = ActiveSheet.name
    'Turn off screen updating.
    Application.ScreenUpdating = False
    'Create a chart located on a chart sheet.
    Set aChart = Charts.Add
    With aChart
        .ChartWizard Source:=Sheets("Schema").Range("A2:D7"), _
        Gallery:=xlBar, Format:=3, PlotBy:=xlColumns, _
        CategoryLabels:=1, SeriesLabels:=1, HasLegend:=1, _
        Title:=Title, CategoryTitle:="", ValueTitle:="", _
        ExtraTitle:=""
        'Remove the legend.
        .Legend.Delete
        'Create and format the series.
        With .SeriesCollection(1)
            With .Border
                .Weight = xlThin
                .LineStyle = xlNone
            End With
            .InvertIfNegative = False
            .Interior.ColorIndex = xlNone
        End With
        'Modify the category (x) axis.
        With .Axes(xlCategory)
            .ReversePlotOrder = True
            .TickLabelSpacing = 1
            .TickMarkSpacing = 1
            .AxisBetweenCategories = True
        End With
        'Modify the value (y) axis.
        With .Axes(xlValue)
            .MinimumScale = ValueAxisMinValue
            .MaximumScaleIsAuto = True
            .MinorUnitIsAuto = True
            .MajorUnitIsAuto = True
            .Crosses = xlAutomatic
            .ReversePlotOrder = False
            .ScaleType = False
            .HasMajorGridlines = True
            .HasMinorGridlines = False
        End With
     End With
    'Turn screen updating back on.
    Application.ScreenUpdating = True


 
 End Sub

the RiSoftGantt.Show is a userform which takes value from the userform and paste it in range "A3:D7"


Thank you.