First thing to remember is every preset program is just that, a preset, any preset program can be made exactly the same as any other if the settings and discrim patterns are matched, the presets are basically switch on and go settings. The "Coins" mode is a really good one and should work fine, I use it 90% of the time, I rarely use any of the other presets as for other situations I have made my own custom programs, such as a Pre Dec coin, $1 $2 coin and silver and gold jewellery program. Also a goldies only program and a Pre Decimal only program for extremely trashy sites so I can isolate good targets among high trash conditions.
The settings I use for parks in "Coins" mode are.
Fast: on
Deep: off
Target Separation: High trash if there is heaps of junk or low trash if there is minimal junk.
Tones: Combined
Sensitivity: Auto
As AngerManagement recommended, get some modern coins, silver coins, silver rings to use as test pieces so you know the target ID's that they give, such as $2 coins will be say 12:36-12:38, $1 coins will be 12:39-12:40.
Read the manual, then read it again and again and so on until you understand the menu and related settings. If you think you have changed settings too much and the detector is not performing do a factory reset.
Hope this helps and best of luck with your detector.