This transmitter and receiver have a fixed function and are not prgrammable. What function does your application require? This could be interfaced to a microcontroller or depening on whats needed, I could suggest a different device that may fit the application better.
300 yards...that's 900ft....probably won't happen legally with those two parts...at least not reliably. Most people expect wireless devices to be reliable as a wired device. Let's put it in perspective...a wired device with unbroken wire is very reliable at close to 100%. A wireless device won't touch that. A bating average in baseball of 0.95 would be great. But for wireless...as the perception is "as good as wired".....even at 95% batting average many people find it INTOLERABLE if they don't have some ability to re-orient and re-transmit in case of failed transmission.