A waistcoat with chain and pocket square distributes attention across several upper areas in this picture. A pale shirt supports a dark tie, while the waistcoat fills the centre below the jacket. Beside it sit a pocket square, small lapel detail and curved chain. The arrangement makes the distinction between basic shape and additional accents particularly clear.
Build your own version initially with shirt, waistcoat and jacket only. Decide how much waistcoat you want visible and whether the tie has the right visual weight in the centre. Add the pocket square next, followed by a possible chain. If both details together interrupt the quiet area you wanted, one may be enough. An additional accent is a style choice rather than evidence of quality.
Check how a chain sits while reaching and sitting and whether it interferes with your bag or other pieces. The photograph shows no movement sequence. Material, brand and manufacturing method require separate information; the visible accessories do not establish a bespoke origin.