If you wish to hold your bitcoins during the hard fork event, just withdraw them from the exchanges ( if you are using any)into a wallet like electrum and wait. No need to do anything else. You can choose your side whenever you like.
What you need to be careful is, you need to do it before the HF, or you will be at the exchanges mercy.
If then HF happens and it splits, will a wallet like Ledger Nano S give copies of both or does it have to be a software wallet?