The OEM Samsung Service Manual can be found here: [document|24233|Samsung SM-SMF700U Service Manual.pdf]
In general, if your phone is not charging you should try some initial troubleshooting steps to narrow down the cause:
# Try a different charging cable that is known to be working (this is a cable you have seen work to charge another device)
# Try a different charging brick that is known to be working (this is charging brick that you have seen work to charge another device)
# Try both known-good charging cable and brick on the device
# Try the wireless charging functionality
The most cost-effective (cheap) repair will be soldering if the issue is related to a faulty component. This is an extremely technical repair, so unless you are already skilled or confident in your ability to perform this service on your own I would recommend taking it to a repair shop that does microsoldering.