The source positions this as a soap for oily skin and oily scalp, and specifically as a more intensive wash that people choose from time to time, not as a mandatory daily cleanser. Oily scalp with dry ends is a common combination, and the product is described as suitable for exactly that: wash mainly the scalp, where it removes excess sebum and styling residue, and wash the lengths with the leftover lather instead of rubbing the bar over them.
As for frequency: with oily skin, a few times per week, or after sauna and workouts, is a sensible starting point. If your skin or hair is very dry, sensitive, color-treated, or easily irritated, start with once a week and alternate with a milder cleanser. The source is explicit that alternating is the right approach in those cases and that you should stop using the soap if any irritation appears. Keep it away from the eye area entirely.
Soap-based cleansers leave a different after-feel than gels. If the skin feels tight after washing, you likely used too much or washed too often; reduce the frequency and apply a simple, fragrance-free moisturizer. The oak and chamomile extracts in the formula are present to support a less greasy and calmer feeling after washing, but they do not change the basic rule of introducing an intensive product gradually.
If you have a diagnosed skin condition, take medication, or are pregnant or breastfeeding, consult a specialist before adding a strong cleansing product to your routine.