You need to turn off your laptop and disconnect the power. Remove the old battery, carefully install the new battery on the battery case, and connect the wiring of the new battery. If you don't understand the above steps, you can search for the video about laptop battery installation on YouTube. Maybe it will help you.
MacBook Air 13 inch A1466 (Mid 2012, Mid 2013, Early 2014, Early 2015,2017)
MacBook Air 5,2 13" A1466 - (Mid 2012) ---MD231LL/A (1.8 GHz Core i5) / MD232LL/A (2.0 GHz Core i5) BTO/CTO (2.0 GHz Core i7) MacBook Air 6,2 13" A1466 - (Mid 2013) ---MD760LL/A (1.3 GHz Core i5) / MD761LL/A (1.3 GHz Core i5) MacBook Air 6,2 13" A1466 - (Early 2014) ---MD760LL/B (1.4 GHz Core i5) / MD761LL/B (1.4 GHz Core i5) MacBook Air 7,2 13" A1466 - (Early 2015) ---MJVE2LL/A (1.6 GHz Core i5) / MJVG2LL/A (1.6 GHz Core i5) MacBookAir 7,2 13" A1466 - (Whole 2017) ---MQD 32xx/A, MQD 42xx/A, MQD 52xx/A
MacBook Air 13 inch A1369 (Late 2010, Mid 2011)
MacBook Air 3,2 13" A1369 - (Late 2010) ---MC503LL/A (1.86 GHz Core 2 Duo) / MC504LL/A (1.86 GHz Core 2 Duo) MacBook Air 3,2 13" A1369 - (Late 2010) ---MC504LL/A BTO (2.13 GHz Core 2 Duo) MacBook Air 4,2 13" A1369 - (Mid 2011) ---MC965LL/A (1.7 GHz Core 2 Duo) / MC966LL/A (1.7 GHz Core 2 Duo) BTO/CTO (1.8 GHz Core i7)
New battery: For use a new battery, youd better try a few cycles of discharging to 5%. then charging up to 95%. So that it can be activated completely Overuse: Do not always run out of a battery to 0%, this would make it damaged or usage life shortened Charging sequence: when charging, first install the battery, then turn on the power, when fully charged, first cut off the power, then pull the power plug. Long-term storage:Please store the unused battery fully charged.(Charge it once a month) Do not store at low power to prevent reduce the lifespan of a battery Charger: Do not replace the laptop adapter casually. If the original adapter cannot be applied due to malfunction or damage, please replace the models, so as not to reduce the service life of the battery due to incompatibility.
Install A New Battery MacBook air 13 inch Battery-- A1466/A1369/A1496/A1377/ A1405 Laptop Maintenance Tips