Entering this information will set the length of your luteal phase and affect all of Clue's future predictions for your fertile window.
Here's how to manually set your day of ovulation in Clue.
1. Go to the calendar
2. Find the date where you had a positive ovulation test
3. Tap this date twice to edit data
4. Go through your tracking options until you get to 'Tests'
5. Select the "ovulation test pos." button
If 'Tests' is not showing, tap the "+" at the end of the tracking options, or go to Menu-> Tracking Options-> Medical and make sure that 'Tests' is switched on.
Note that the "ovulation test pos." entry will set your day of ovulation to the following day. This is because over the counter ovulation tests indicate ovulation is within 24 hours. If there are multiple 'ovulation test pos.' data points, Clue will use an average of those to calculate the length of your luteal phase.