How can I upload waypoints from QGIS to my Garmin GPSmap 62 by using GPS Tools in plugins? I only manage to do it with an older Garmin GPS.
I wonder if you are able to download data, in any case this link describes how to connect a garmin usb gps in Qgis
As everyone else has told you, a little bit of more information could be useful in order to help you.....
Your question is a little vague as commented above, but I have been successful at getting waypoints (a qgis layer) into my magellan triton using the following process. I obtained the qgis plugin "PostGPS2gpx". This converts a selected qgis layer into a gpx file which can then be loaded into into your handheld gps with the software that came with your device rather than trying to cable directly to qgis.