I think Christo has already touched all major points....
One more think about:
Espressif has recently released a new SoC which is also RISC-V based and very affordable:
https://www.espressif.com/en/products/socs/esp32-c3This SoC is pretty similar to the Pine chip when it comes to Specs. I already have a few dev-boards and sooner or later support will pop up in mbf-freertos but it is not something I have started working on.
There are already dev boards available for $3 on Aliexpress.
As it also uses the same SDK as the other Espressif Chips porting will be a lot easier than for a brand new chip.
Anyway, back to your questions, if you want to get your feet wet with the pine chip then the easiest way is to port the controller definitions that you want to try to Freepascal and add those defs in the embedded target.
This will allow you to do the usual stuff, blink LED's, SPI, I2C and will likely keep you busy for a while (and is also great fun)
I can help you to integrate your pascal unit into freepascal, this is an easy task, you only need to know a few files that you need to change.
For using WiFi on the chip you are better off with FreeRTOS but this task is a bit more complicated, so if this is not the highest point on your priority list I'd wait until support for esp32-c is available, then it will be a lot easier for you to actually make the pine chip work.
Michael