A:AnswerI haven’t used this keyboard with an iPad since I have a Magic Keyboard case for my iPad Air 4G. it will work for you as I used the Magic Keyboard without the number pad with my iPad 6th gen. It will pair easily.
A:AnswerThe keyboards I have have to be kept charged. I have some that are eight years old. One should have a cable that came with the key board. If you no longer have that cable, I believe you could purchase one from Apple. Also , you might have a family member, or friend that has one with a cable that would let you test your keyboard to see if that is the cause of it not working.
A:AnswerMake sure the switch is on. If so, look in the Bluetooth section of system preferences to be sure it's visible (if it's on and not visible, there's something wrong with the device). The keyboard section should automatically hook it up. You can only be paired with one device at a time - Blue Tooth is monogamous. You can unpair and re-pair as often as you like, if you don't mind the hassle.