Don't worry.Samsung and iPhone are very popular mobile phones. So there are many ways to help you transfer files.First,both Apple and Samsung's official tools can help you transfer files to your computer,then transfer data from computer to device.Second,there are many phone to phone data transfer tool can help connect two device and transfer data.
If you want to transfer data like contact, text messages, books(pdf&epub),music, videos, photos from iphone 5s to samsung a10 from computer, you can try Coolmuster Mobile Transfer. You just need to install it on your computer, start it. Link both of them to the same computer via usb cables, enable usb debugging on them. Then you can transfer data iphone 5s to samsung a10 directly from computer.