Your goods might well have been brought all the way from China (silk) and the spice islands (spices such as Cinnamon and Cloves). The Venetians were merely the middlemen on the long Silk Road from Asia and handled the Mediterranean leg of the journey from the Black Sea (Kaffa and Trebizond) via Constantinople and Syria until that route was mostly closed by the end of the crusader states and the Venetians lost their trade concessions. Also until they were shut out Egypt in they were able to exploit the route to India via Cairo. More locally the Venetians were deeply involved in the grain trade, the city after all could not grow its own food and when it could not extract enough from its territories on terrafirma the state would negotiate the purchase of grain, often at a huge markup, from Sicilian merchants and others. Later on Venice began to produce its own luxury products for sale, things like Murano glass which is still famous today.

As for where they sold them the main route went from Venice, over the alps and into Germany and Austria and hence indirectly into Eastern Europe. They also sold directly to Spain and had direct routes to the Netherlands and England, whence the Hansa sold their goods on into the Baltic region.