I am replacing an old thermostat for ac/heating. There are 5 wires red, white, orange, black, green.
My new unit (Noma programmable thermostat).

The instructions indicate points of connection using red, white, yellow, green.
My confusion is, where do I connect orange and black, because there are only wire connections on my new unit, marked, green, red, yellow, white.

Is this a heat pump that you have?

My apology, I should have mentionted that it is an electric forced air furnace.

It is an electric furnace.

Is it only heat and cool? A heat pump will heat and cool but is backed by electric(gas & Oil,also)

Normally red=R(24V power on stat, grn= G to fan relay, WhiteW= heat, Yel=Y cooling contactor. What terminals were the colors on on the olsd stat? Org is usually o on stat to energise rev valve and the blk could be common. Possibly need to see haw the air handler is wired to be for sure