My nema 17 motors have 6 wires and no connector how can i connect it to my ramps board?

6 wires usually means that you have 2 coils, each one with a centre tap (effectively making 4 coils, with each pair hooked in series). You need to ignore the centre tap wires (don't connect them to anything, and do not connect them to each other).

I would use a resistance meter (multimeter on resistance scale) to figure out which coil is which, and which are the outer pins of the coils.

This page might be useful: [reprap.org]