To get this achievement you need to perform Daily Challenges to gain enough points to earn a Bronze Medal. You can earn 1 Bronze medal for each month you play so you will need to play for a minimum of 12 months to earn the achievement.
The game officially only allows you to play challenges in the current month but there is a way to play the Daily Challenges in previous months by changing the system date to a previous date, this allows you to gain the 12 medals required quicker.
This method is the same as most of the other Daily Challenge Badge guides suggest, for months from Apr 2017 onward you can complete the daily challenges as normal, for months prior to Apr 2017 there are 3 rules you need to follow else the game gives you the message 'There was a problem loading Daily Challenge Data'. You will then have to close and re-open the game to do another challenge in that month.
The first 2 rules for date prior to Apr 2017 are:
Firstly you can only perform 1 challenge at a time and once selected you cannot change to another challenge. If you fail it you can re-try it again (there is a Re-Try button) but once complete, or if you try and change it, you will get the message above every time you click another challenge.
Secondly you have to start the game in an 'active' time period or you will get the message above as soon as you select the daily challenges. This 'active' time period appears to be April 2017 onward but this might change.
These are the main rules, so to help here is the process to follow:
0. Make sure system date is set to an 'active' time period (Rule 2).
1. Launch game and wait for the Summary screen to appear.
2. Change system date to required month and change day if required to access more challenges for the month.
3. Select the Daily Challenge option, then select required day on calendar and finally a Challenge for that day (Rule 1 and also note Rule 3 below).
4. Set system date back to an 'active' time period before completing challenge. (See NoodlesJr Tip in comments - this reduces the points needed to reach the medal target)
5. Complete the Challenge - Remember if you fail you can hit the Re-try button else you will need to close and repeat from point 1.
6. Once complete the points are awarded and you can close the game.
As you have changed the date back to an 'active' time period in step 4 you can repeat from steps 1 until you reach the Bronze medal.
The third rule is you cannot select a Crossword challenge outside of the 'active' time period as they do not work. If you select a Crossword challenge you will get the error message above and you will need to close the program and start from point 0 again.
This final rule means you cannot get the 500 Point Bonus for completing a day so it will take more challenges, repeating the sequence above, to get to the target for Bronze.
It also hinders getting a Silver medal and Gold is out of the question.
Thanks to NoodlesJr tip Silver can now be reached easily too and Gold is also possible.
If you follow these rules you should not have too many problems, but for an easier time you can just tow the line and complete each month as it comes and forget this guide even exists.
Well that's it, a lot of text for 20G, good luck.
You know the drill: Any negatives let me know first etc, etc