How am I gonna make my iPhone switch on again

Hi!

Typically with iPhone's that are not turning on there's a few basic things to try out so you can diagnose the issue that your phone may be having.

# Check that the charging cable and plug are actually working. Try them both on a confirmed known working device, if they are then you'll know that yes your phone does indeed have a problem.

1. Take a look to see if there's anything stuck inside your phone's charging port that could stop the phone from charging properly. Over time, dust and debris can build up inside there and block the charger from making a proper connection. If you do notice something stuck in there; take a long sharp tool, like a tweezer and gently push out anything that may be stuck inside the charging port. Be extra careful when doing this as it is possible to damage the port itself while doing this though!
2. If both haven't helped, your phone's battery may be the problem. You can test this by opening the phone by following the steps on the ifixit repair guide for this device which you can find here: iPhone 5 のバッテリーの交換方法 However, instead of removing the old battery - simply disconnect the old battery from the motherboard, and connect the new battery. Attempt to power it on and if it works, try charging the phone.
3. If the phone isn't charging, try a new charging port instead.
4. If neither worked then most likely your phone may have a motherboard issue and may need to be professionally repaired. From my experience possible liquid damage or component failure may be the culprit if none of the above helped you.

If you have anymore questions please feel free to reach out and I will do my best to help.