ESP8266 NodeMCU LoLin

hello, i have a question about this esp8266 part, how do i download the esp8266 board for development because at the board selection button i can only see arduino and picaxe board options, but i want to use the espboard because it is the central microcontroller.

or is there another way to run my codes with the arduino board module when it is not the central microcontroller am using ?