Wash it with a mild dish detergent first to remove any mold release that might be on the surface. If it is there it will not glue well. I always pin resin. It is overkill and unnecessary in most cases but I tend to over-engineer. For glue, superglue will work, and so will two part epoxy resin (or plastic depending on the country). Try not to use the super watery superglue. It will run off the surface. I prefer gel superglue for this application. Rubber band or clamp the parts while the glue is setting. My two cents and I hope that helps.
Snitchy sends.