I just bought 300 square feet of engineered wood. The brand name is rapid loc and it is natural oak wood that is snap in place. It does not require any glue or nails. But from watching videos on youtube I noticed that many of the installers put glue between the grooves. Will that make the boards stick together better and make it more water resistant? The manual doesn't say anything about putting glue between the groves but I feel it would do a better job in installing the wood.

I would definitely check with the manufacture for directions. Some locks systems recommend gluing in wet areas to help with moisture.

This stuff locks together so glue at the seams is not required. The only time it is required is for a tongue and groove floating floor.

To expound on what Mickey pointed out....Some manufacturers REQUIRE gluing ,( even with a click system), in "wet areas", ( baths, service areas, mud rooms, some kitchens ). Especially required almost all the time in baths, to keep warranties in effect, due to standing water on surface of floor, and dramatic RH swings, in a closed up bath.