You can open a lot of files simultaneously in Excel (there is probably an upper limit but I don’t know what it is!).
But, they appear “in” the Excel window rather than separate workbooks, which is what you would get following mgmcc’s suggestion.
At the top right of the Excel screen you should see the usual minus sign, square (or double square), and cross for manipulating the window. Just below that is a second set. This second set controls the files “in” the Excel window e.g. clicking the minus sign minimises that file and reveals a second file you have open. The minimised files shrink to the bottom left, but again within the Excel window.
You can fiddle with these controls just the same as any other window, but everything stays “in” Excel.
Not the easiest thing to explain, but I hope you see what I mean.
Yeah I'll have to open the programme twice. I want both windows visible to swap info in a spreadsheet in order to produce a new one. Strange that you cant view 2 open files at the same time. You can do it in Word.