Deleting items from an external hd?

I am a new user of Mac. (after using windows my whole life) so things are still very new, very confusing, and very frustrating!
After finding out all my harddrives need to be re-formatted, I found out that items deleted from an external harddrive dont actually get deleted like they do in windows...
without completely formatting every 1tb harddrive when I want to delete a movie, picture, etc...how do I just delete a single thing?
I know this is a stupid question, but I cant figure it out or find the answer anywhere. I appreciate any help! thanks

All you need to do is find the file/folder and drag it to the trash. Just as you would with any other file/folder on yourHD.
Or right click/ctrl click and contextual menu 'Move to Trash'

Cheers

And empty the trash before you eject/disconnect the drive.


If you disconnect the drive after deleting, then empty the trash, the next time you connect the drive, you'll find that item will appear in your trash again.

Same as windows, it's not gone until you empty the trash/recycle bin.