Updated:
On a via ferrata, fixed cables and ladders lead through terrain that an ordinary walking path cannot. Allmenalp above Kandersteg and the Mürren route are two local options, each with its own grade, approach and descent. Read about the specific route before choosing it. A qualified guide is the right starting point if you lack the skills.
Both routes are exposed and physically demanding. Equipment alone is not enough: you need suitable skills, an escape plan and dry, settled weather. If heights already bother you on ordinary paths, choose a different mountain outing.