Does anyone know what country this is? [opgelost]

Thailand
You can use the Image search  of the site even with only one side will work

thank you !

Any idea how I decipher the date for Thailand

No

My coins after I find the coin on Numista catalog (sometimes searching for the diameter, weight or image search) I compare with the list of giveing years.

Example

https://en.numista.com/numisdoc/calendar-thai-33.html

Thank you all, Im quite new to this, so this forum is really helpful, your time and help is much appreciated