As hrturizam writes, Biokovo Nature Park (and its main attracion called Skywalk) will be closed untill April 2022.
The glass promenade is not suitable for tourist activity during the winter season. That's why it will be not available for a visit during the next 5 months.
The Skywalk has been the most glamorous newly opened tourist spot in Croatia in 2021. Thousands of visitors enjoyed walking on a glass bridge with the panoramic view of Makarska Riviera and nearby islands.
If you want to visit the attraction in 2022, I recommend planning a trip in April or May, since the place will be crowded during the peak summer months next year.
Find more info in my Biokovo Skywalk guide.