There is loads on “ Arduino getting started 4809” which mr Google will find for you .
The really excellent “ Mighty core “ is worth a search too ! - allows you to install a boot loader* (via that single UPDI programming pin ) such that it can then be programmed using a serial port in the same manner as , say, a UNO.
A UNO/NANO can be configured as a UPDI programmer , and run from the Arduino IDE.
Again Google will find this for you
( * a bootloader is not reqd, but this makes life easy)
My 4809 Experimenter/developer board 
