To get the sheets, you can use a WorkBook application variable with the Excel Scope (in its Output property). (assuming wb is the variable name for the workbook) Then, use wb.GetSheets() which is a collection of the sheet names as strings. You can filter, sort, or other things with it since it’s an array. You can run them through a For Each and Read each sheet, or in your case, rename each sheet. An example of for each would be like For each sh In wb.GetSheets, or to just get the first sheet you can use wb.GetSheets(0).
Note: GetSheets() can have errors if the excel file has a chart as a sheet, which I have run into before.
To rename the sheet, you can look into the Excel extended activity package or other Excel packages out there in the Go/Community Feed which may have a Rename Sheet activity. Or if you don’t want an activity, just use the Alt-key combination to rename the sheet ("[k(alt)]hor"+newsheetname+"[k(enter)]" I believe is the key combination if I remember right)