Select a specific ROW item in file explorer

In script code, you can find the item based on its Id value using FindId() method,

function explorer()
{
    var explorer = NameMapping.Sys.Process("explorer").Window("CabinetWClass", "C:\\Project Flow", 1).Window("ShellTabWindowClass", "C:\\Project Flow", 1).Window("DUIViewWndClassName", "", 1).Pane("Explorer Pane").Window("CtrlNotifySink", "", 5).Window("SHELLDLL_DefView", "ShellView", 1);
    var listview = explorer.List("Items View");
    var item = listview.FindId(5);
    if (item.Exists) {
        item.Click();
    }
}

You should be able to do the same in Keyword Test.

See https://learn.microsoft.com/en-us/windows/win32/winauto/microsoft-active-accessibility-and-ui-automation-compared for MSAA

If you add the value of property WndClass to MSAA (in Project Settings -> Properties -> Open Application) for explorer. You will be able to access the individual components. 

Depending on your explorer view layout, you can access the index of the item.

On a seperate note, what's the reason for accessing that folder via explorer?

In Keyword Test, if you use code expression, you can create a string which has similar naming to your file

Index will be shown here,

If you look at the log output, it's similar to your file/folder name i.e. "FP64_2023_02_20".  If you know how the file name is generated, then you can construct a string similar to the file name - then use this to compare the two files. Just a suggestion.

Change your Explorer view to List (actually this doesn't make much difference)

FindId(5) will return the Id object of 'TestProject4'

Find("ObjectIdentifier", "TestProject4") will return the object 'TestProject4' - I should have mentioned to use this method instead, sorry.

function explorer()
{
    var listview = Aliases.explorer.listItemsView;
    //var item = listview.FindId(5);
    var item = listview.Find("ObjectIdentifier", "TestProject4");
    if (item.Exists) {
        item.Click();
    }
}

Note, that Aliases.explorer.listItemsView is the object that's highlighted in red

Keyword Test will look something like this,

In this example: Index values are like so,

To get the object of "TestProject5", I will call FindId(6).

Do not create a name mapping for 'TestProject5'.

If the latest folder always appears in the 5th position, then you can call FindId(4) to retrieve the object  of "FP64_2023-02-20_002"

If you had a name mapping for "FP64_2023-02-20_002"; next latest folder might be named FP64_2023-02-20_003 or FP64_2023-02-23_001. Therefore, the previous name mapping will be redundant.

If the View or ordering changes in Explorer, then the results will be different!

Your folders are dynamically created, and it will be "easier" to use script code (or code snippet) to get the latest folder.

Here's a small video clip of it working.

When you run the following code, is it highlighting the correct items?

function explorer()
{
    var listview = Aliases.explorer.wndtest.test.DUIViewWndClassName.Explorer_Pane.CtrlNotifySink.ShellView.Items_View;
    Sys.HighlightObject(listview); // Correct item highlighted?
    var item = listview.FindId(4);
    if (item.Exists) {
        Sys.HighlightObject(item); // Correct item highlighted?
        item.DblClick();
    }
}

Did you insert the following line of code, Sys.HighlightObject(listview); // Correct item highlighted? As shown in my previous example?

This is to test to see whether the correct item is highlighted.

What properties have you defined for Items_Views?