You can't do this with the Alarm mode within the default Clock app in iOS. However, you can do this using either the Reminders app or the Calendar app.
First of all, if you want this to work as a wake-up alarm in the same way as the Alarm in the Clock app, you need to change the sound associated with the app. If this is what you want, these are the steps involved:
- Go to Settings
- Tap on Sounds
- Scroll down to and tap on either the Calendar Alerts option or the Reminder Alerts option
- Scroll down to the list of Ringtones (past the alert tones) and select the ringtone you want to use as your alarm. If you want to use a traditional 'alarm' sound you will need to scroll to the very bottom and tap on Classic to select the one you want.
- Once you've selected it, go back to the main Settings screen and exit
NOTE: Keep in mind that when you make the above change it'll be set for all Reminders or all Calendar Events - so you will need to decide which App it is you want to use with your new 'alarm' sound.
Setting your schedule
Now go to the app you chose for this (i.e. either the Reminders app or Calendar app) to set your schedule. The process for either will basically be the same, but in these steps I'll use the Reminders app as my example.
- Launch the Reminders app
- Tap on the + sign to create a new reminder
- Give it some sort of meaningful name
- Switch on Remind me on a day
- Select whichever date is the very next Monday you want the alarm to go off on
- Set the time you want it to go off on that Monday
- Tap on Repeat
- Select Every Fortnight. (see Notes below)
- Now repeat the same steps for each of the days, making sure you pick the date you want the alarm to go off and choosing to repeat it every fortnight
- Exit the Reminders app. Your schedule is now set.
- The Every Fortnight option may be a localised option in my region. If it's not available, select whichever option is for two weeks. If you have no such option, you can tap on Custom and then choose a Frequency of Weekly and select Every 2 weeks.
- If the actual time is the same for each alarm, regardless of day, then at Step 8 you could choose a custom repeat of Daily that repeats every two days. In this scenario you could get away with a single reminder and totally skip Step 9 altogether.