ApExcel is just the name you assigned to the application object so you can use it in subsequent lines. There was probably a "dim ApExcel As Object" that preceded the code you found. This defined ApExcel as the name of an object which is then set to represent the Excel application itself.
The approach I use for the sort of project you are doing, is to go through all the steps manually so I know exactly what I want the code to do, and in what order.
Then I start filling in the steps with code.
It's very helpful to record the manual steps and then view what you've done in the VBA editor. However much needs to be changed from there, particularly anything to do with variables.
Record the importation of a .csv file, and continue to record saving it as an .xls file (which you'll need if you want to keep your formatting). Then look at the code.
Excel's VBA help has a lot, but I find it difficult to find things, and the explanations require a working background that I found difficult to get in one comprehensive overview.
Google an Excel vba primer, look for one that has examples like the sort of thing you are looking to do. There are Microsoft Excel MVP websites that are invaluable (Pearson, DeBruin, McGimpsey, etc) Check out the board at vbaexpress.com and the microsoft.public.excel.programming newsgroup
When everything is automated, use an Auto_Open or Workbook_Open macro which will run as soon as your workbook is opened by the script that created the .csv file in step 1.