It is always good practice to the specify the exact version of Hyperion you on(e.g FDMEE 18.104.22.168.210, HFM 22.214.171.124.204).
Without knowing all the details of your application(e.g rules etc) at a simplistic level:
Get the ending balances of the year which you will not have any more (e.g If you Just will have FY15 and FY16, then you need to ensure you get all the ending balance of FY14 and load those into FY14 Dec of your new application or your opening balance for FY15.)
Then you can manually extract(you could use FDMEE data sync too) your Data and extract journals from your old application and load into your new application,
If you have other artifacts(Data Forms) you can use LCM to move those over.
Hopefully that helps you get started, good luck and let us know how you make out.