Brass fitting

What is the right technique of connecting a Brass Fitting?

AB-033-1/2-3/8-PP : Brass Fitting Male to male Reducer 1/2 - 3/8NPT — Pneumatics-pro Inc.

APPROVED VENDOR BRASS FITTING KIT,ASSORTED - Metal Pipe Fitting Kits - GGM6AZF6

Hydraulic Brass Fittings - Manufacturers, Suppliers in Dubai, UAE

Brass, 1/2 in x 1/2 in Fitting Pipe Size, Coupling - 46M497

Brass Fitting Supplier, Pipe Fittings

Pex Fittings Tee Brass Fittings Barb Crimp Pex Pipe Fitting - Temu

Napoleon W445-0031 Brass Fitting 3/8 MF x 1/2 MF —

Brass Fitting Parts - ABLE BRASS INDUSTRIES

1/2 Quick Disconnect Brass Fittings, Spray Gun Fittings

Mid-America Fittings - A Brass Fittings Manufacturer

Same as (103-E Female Hex Coupling), AB-039-3/4-3/4-PP : Brass Fitting Female Hex. Straight 3/4NPT, SPECIFICATIONS, Category : Brass Fittings, Brand

AB-039-3/4-3/4-PP : Brass Fitting Female Hex. Straight 3/4NPT