Suppose you put the data into Excel.
In Math'ca type
data = Import[at which point go to Insert menu, then select File Path, then (in the dialog box) doubleclick on the Excel data file
then type ] to close the Import bracket.
The input line will look like:
data = Import["C:\\My Documents\\Excel file.xls"]
Put the cursor anywhere on the line and hit Shift+Enter.
Math'ca will take a second or two to read the data.
You will have created a Math'ca data table named data. For example, typing
data[[1]]
then shift+entering will print the first row of the data. (If that doesn't work, try data[[1,1]].) Likewise, data[[1,4]] (or data[[1,1,4]]) will print the 4th column on the first row.
