Why do my apps all ask for update at the sane time and do not proceed?

iPhone 5s, still working good. Just downloaded iOS 11.3. All of my apps have been unusable since this morning, when I downloaded letest iOS update. I click on the icons to open, and they start upgrading, but unfortunately upgrade never got to completeness. It is stuck and I just can’t use anything on my phon. Connected to Wi-Fi and charging, still not moving anywhere. What shall I do?