Hi everybody!
We purchased Piazzetta Sveva stove and had it installed in October this year. Since nobody went over the stove with us

I focused on reading the forum and manual instead. I have to admit that the forum can be a little bit overwhelming for the beginners especially when all the possible stove tweaks are mentioned. I'm trying to focus on the basics for now... I read in the manual that sawdust accumulation on the bottom of the hopper should be avoided... but there is no explanation of how it could be achieved. Every bag of pellets have sawdust in it and it's virtually impossible for it to be stopped while loading the hopper. So I assume there must be some other way of cleaning the hopper itself? Any suggestions?
First you should tell us what pellets are you using? And if they're dusty you should consider switching brands.
The Sveva is mechanically the same as the Sabrina which a few of the folks on Hearth have, including me.
Having said that, the Piazzetta is not particularly finicky with sawdust, aka fines. You certainly want to avoid it when you can, and then vacuum the bottom of the hopper every once in a while, first at 2 week intervals, then adjust based upon your usage. To be honest, I've only vac'd the hopper twice in 5 tons of usage. You'll have to remove the screen that is held with 4 screws in order to vac.
My routine is to buy pellets with as few fines as possible. I hate having the dust fly up when I dump a bag in the hopper. In general, all Super Premium pellets are low ash and low fines. One brand I loved last season was GranulesLG, which Harvey notes above is good this year too. The bag is clear so you can see it has no fines. Really. Last year I posted a pic of the LG as the pellets were like little pieces of broken french bread, no dust whatsoever. Premium pellets can have twice as much ash and fines, so the variance between pellet brands is quite wide and you'll have to buy a few bags to try them.
This year I have 3+ tons of doug fir Blazers, which are very clean, and 2 tons of FiresideUltras, which are notoriously dusty, but the first two bags I have burned this year were better than I recall. I tested some MaineWoodPellets, aka MWPs last season and they had a lot of fines, ½ cup a bag!
Once you've settled on a clean pellet brand, then you should be careful as you load your hopper. Often the fines you may have are in the bottom of the bag, so if you don't throw in that last bit, you can keep most of the dust out.
In the extreme case you have dusty pellets, you can try putting a vac hose propped on the edge of your hopper, while you slowly pour in your pellets. If you're careful a lot of dust which is light, will get sucked into the vac without sucking in your pellets.