Usually they just crimp on. What I do is strip just enough insulation so the wire makes good contact inside the connector, them I tin the ends of the wire with solder, crimp the conector on with the insulation touching the end of the connector and then shrink wrap over the insulation and the end of the connector. I also put a dab of dialectric grease on the male end before making the connection, that way the corrorsion is slowed. Buy the highest quality crimping tool you can afford, believe me it makes life a lot easier! I have a wonderful old Klein Tool crimper I got at a garage sale for a buck.
Terry
J'ville, Fl.