I have new phone but i recently broke it. So I did a back up so I can transfer my new data from my new phone to my old phone

If you "broke" 'your new phone, there is no way that you could then make a backup of the phone. So, you need to provide more details about what you mean by "broke".

It is important for you to remember that if your "new" phone was running a higher iOS system than the iOS version on your "old" phone, you will not be able to use the backup of the new phone to restore the old phone.

So, please clarify on what iOS version was installed on your new and old phones.

Follow the steps here: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Defnottkris Said:

"I have new phone but i recently broke it. So I did a back up so I can transfer my new data from my new phone to my old phone: How do I apply my backup from my new phone to my old phone?"

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How Exactly would you Define "Broke"?:

"Broke it?" How so? Is it physical damage? Or is it not charging? Or is is something else?

For reference...

Troubleshooting Slow iPhone Power:

The iPhone battery will not charge, unless it is plugged in and charging. With lots installed, the charge would be slower. It would also depend on the battery health and how you are suing heal it is charging..  Go Here: iPhone Battery and Performance - Apple Support - Scroll down to "Your battery's maximum capacity"

View the Battery Health:

Apple recommends you get a new battery, once the Battery Health reaches 80% or lower. When the Battery Health is 80% or lower, it is time for a new battery.

1. Go To: Settings
2. Tap: Battery
3. Tap: Battery Health
4. View: [the percentage]
5. Is it 80% or less?  If so, it is time for a new battery.

Troubleshooting the Battery:

• iPhone Battery and Performance - Apple Support

• Charge and Monitor the iPhone Battery - Apple Support

• About the Battery Usage on your iPhone - Apple Support

• About Optimized Battery Charging on your iPhone - Apple Support

• If you see "Your iPhone Battery may Need to be Serviced" - Apple Support

• Use Low Power Mode to Save Battery Life on your iPhone - Apple Support

I believe Apple only considers the battery degraded if the battery capacity is less than 80%, not less than or equal to 80%. Ex. your battery will only be replaced under AppleCare or Limited Warranty if the capacity is 79% or below.

iPhone Battery Repair & Replacement - Apple Support