Sentinel-3 download

Hello my dears
I would like to download the Sentinel-3 data from SST and altimetry but I still can’t get it.
I need some help.

Did you go to https://scihub.copernicus.eu/dhus/#/home ? You can select the sentinel (1, 2 or 3) satellite and sensor you want for the specified period, crossing the specified (or not) area.