if you are unsure about any of the technical stuff, please read this guide before doing anything.
http://blog.nem.io/getting-started-with-nem/it explains some very important stuff and also shows how you are supposed to import your account to get your nem. if anyone says they are unsure what to do, post that link.
Very clear and informative.
Are acceptable all three ways for good backup:
A) display and copy Private Keys of all of my accounts from wallet in text form?
B) send funds from all secondary accounts to the primary account and backup only one Private Key of the primary account
C) "Export Wallet" zip as it is in the tutorial