I did need to watch an install video via YouTube as it wasn’t really clear to me as to how the plastic parts fitted into the runners. Apart from that we were delighted with the blind, the delivery and quality were spot on.
Blind was different slightly from the previous one saw installation took a bit more thought
I was forced to buy a replacement blind for a perfectly good one on which the cords had frayed. I think Velux should offer a reasonably priced repair service or a trade-in service.