what do you suggest on using glue or nail on the engineer wood

Pretty broad topic there point, depends on the subfloor type, and what each manufacturer may call for.

I always suggest when doing the initial consultation and labor quote, to staple over wood substrate and urethane adhesive over concrete.

There are some engineered that you cannot staple. There are some you cannot float. There are some that you can do all three types of installations with.

I ALWAYS CONFUSE ON WHEN TO PUT NAIL OR GLUE. I ASK THE SUPPLIER ON WHAT I CAN USE BUT THEY SAY CAN USE BOTH. WHAT IS THE APPROPRIATE WAY FOR ENGINEER WOOD 1/2 " TO DO NAIL OR GLUE?

I wouldn't use a nail in engineered. Staples!!

You never said what the substrate is... wood or concrete??

The substrate would be the determining factor for me.