What's the best way to take a Xara mockup for a phone app, which can be exported to a png and paste that on a photo of a phone.

For example, here's a nice photo of a phone, from Unsplash:https://unsplash.com/photos/15q2ZCDbQFU

I then want to show this image https://i.imgur.com/mSiAVlp.png on that phone.
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I have tried using the perspective tool, but that ends up making my image look like it is an old 8 bit game - all the lines are jaggered.

Is there an easy way to do this?