Learn by editing existing reports, like ARINVDO.RPT.

As Jay suggested, editing an existing report is the best way to get started.  Make a copy of it and poke around.  Then you can look at some of the concepts that were probably covered in your tutorials, like data selection, grouping, parameters, subreports, etc. 

To get to know the data, download the Application Object Models for your version here: https://support.na.sage.com/selfservice/viewContent.do?externalId=19194&sliceId=1

If you want to change a Form such as AR invoice (ARDINVO) or an Order or PO, you can save it under a new name and run it through the original Sage 300 interface.

If you want a completely custom report, add it to the Sage desktop by right-clicking where you want it and choosing New > Report, and then browse to find what you saved.  For this, you need to understand the report parameters, unless your report doesn't need them.

If you simply want to modify an existing report as a permanent change, you can save and/or test it through the original Sage 300 interface by saving it in your Customization directory (you can find more info about that in Sage 300 Help).

wheumann said:

you need to understand the report parameters

Hi Wheumann,

How do I know what report parameters are required by the report? Is it in the .ini files? For example for Purchase Orders, that is PORPT.ini?

Thanks.

Yes

how to download custom crystal report sage300 ?

Your question doesn't make sense.  Crystal reports are not downloaded.