Keep it within reach

Install Counterbook.

Add Counterbook to your Home Screen to open it like an app, without finding the site in Safari each time.

On your iPhone

Open Counterbook in Safari. This install flow is in Safari, not another browser.
Tap Share. Depending on your Safari layout, Share may be inside the Page Menu.
Choose Add to Home Screen. If it is missing, use Edit Actions to add it.
Enable Open as Web App, then tap Add. Counterbook will appear on your Home Screen.