NPS query

Yes, You can avail the benefit under sec 80CCD (1B) if you invest in tier 1 NPS.

For invest in NPS

You have to fill the application form and provide the relevant KYC documents at your nearest POP-PS (You will find the list in PFRDA portal).

Recently eNPS website have been opened where you can open account and invest online.

The above answer is only my opinion. Before making any decision or taking any action, you should consult a qualified professional adviser