When tieing in 14/2 at switch box, what do you do with the neutrals?

Tie together.

We could really use more details here. If this is a switch box you might not have/need any neutrals in the box, just a black/hot coming in and a white w/black tape going out.

If you are only breaking the hots to operate light(s), do not cut the white neutral, leave it intact and remove the insulation that goes around all three wires. Then cut the blacks and hook one to the bottom of the switch, and one to the top, make a "pigtail" for the bare grounds and hook to the ground screw.