how do you recover accidentally replaced files on your external hard ?

in this case a professional assistance is required.

Rapture is a heresy. One must hide within a small group (10-12 people according to saint Seraphim of Sarov from Russia, 10-15 people group according to saint Gabriel Urgebadze from the country of Georgia) in order to escape the unforgivable mark of the beast. No documents; documents are from Satan; burn them (even documents of deceased relatives). No electronics once you hid so that you won't be tracked (even an old broken unplugged TV set from 1970's will show the infamous evil flying antichrist using Tesla's ether). [Saint Vyacheslav Krasheninnikov] Mark of the beast is given with World Passport (grey plastic card with no name on it); antichrist will release prisoners / insane asylum people to help him mark everyone. Police will mark people on highways; food stores will mark people who steal marked food (because marked food can only be swallowed by a marked person who has three strands of DNA instead of two). Reject vaccines, temperature scans, COVID tests (or similar), etc.

A professional service may be able to help you. Recovering lost files is not trivial.

Whether a drive is external or internal, the process for recovering deleted files is the same.

When a file is deleted in Windows it is not actually removed from the hard drive.  Rather the directory entry to point to where the file is located is deleted, and its location is added to a list of available free space on that hard drive.  the actually file is still there.  Windows just does not know where to find it.

There are several free programs, like Recuva, that you can download and run.  They will read through the hard drive and locate any files that are still there.  They can make a list of them and then allow you to "undelete" them by recreating the directory information for you.

Now, because the files have been added to the list of "free space", you have to do this ASAP.  Otherwise Windows may reuse that space and the file is overwritten with new information and lost forever.  Since this is an external drive, Windows is NOT going to overwrite those files unless you tell it to save something to that external drive.

In the future you need to remember Rule #1 in IT.  Copy files.  Do not move them.  Then confirm the copies are good before you delete the original files.

Try recuva

https://www.ccleaner.com/recuva/download

Until then try not to do any unnecessary saves on to the computer as this will overwrite any existing deleted files and reduce your chance of recovery.