1 - Go to https://teamup.com/register/
Fill in the form to set up your Calendar Login if you haven't already.
This is different from your Website Login but you can save the same info in both setups !!!!
If you are just using the calendar on the website, click the icon in the upper right corner of the calendar and log in.
If you want to use the separate calendar on your smartphone, search for the TeamUp app listed in your App Store.
Click + or Add New and type in
https://teamup.com/ks9e4yowuhpzk3oyzz3 - Go to the hike you want to unregister for
Click remove next to your name