I’m not sure what you mean by “I’m click”, but if you are just trying to delete an activity, any activity, it is really simple.  In the app, you just click on the activity title once .  Once that page opens, click on the three dots in the top right corner and select “Delete” from the dropdown menu.  It should be right at the bottom of the list.  On the desktop version of Strava, click on the activity to open it, then click on the three dots on the upper left of the  page and select “Delete”.