1) Do a LISTCAT on the KSDS file and create DEFINE statements to match.
2) Find the IDCAMS DEFINE statements for the original file, copy somewhere else, and update the names (and other parameters where necessary -- such as space allocation).
There is a link to the manuals page at the top of this page. Click on it. Go down the manuals list until you find the VSAM Services for DFSMS. Click on that manual. Find the chapter on LISTCAT. Read it. That tells you how to find out everything about a VSAM file.
Then go to the IBM Redbooks web site. Find a Redbook entitled VSAM Demystified. Read this Redbook from page 1 until you have completely and thoroughly mastered what it says. Repeat as necessary until you do have the material mastered.