Hello,
Just a disclaimer - I don't speak italian, but do understand some parts.
For the question about non-related kwds...the kw explorer finds these through some algorythms between what people search before/after they search those keywords and what content pages that rank for those keywords have.
For the other question, you need to run a good analysis and create a list with your kwds. Then, make sure to carefully skim through it, assign your own priorities for each kw judging by how important they are for your business (ex if you sell bikes the kw "italy bike tour" or "italy bike rental" might not be important for you at all, but might still be suggested by moz). After doing this, you need to order your kwds by overall priority rating. This will make an average between how hard it is to rank for it, the volume of search that kw has, and your priority rating.
For the very top kwds you absolutely want to include the exact kw string at least once in your content (this can be as an alt tag on an image). For the top 2-3 results you'll want to include those exactly in h1's , titles, meta titles, meta descriptions.
For the rest of the kwds, things like including the work "tuscany" will help, but it won't give you a 90+ rating of "keyword optimisation" on that page. Of course you won't be able to be at 90+ for all kwds, but it's ideal to be there for the most important 5-7 kwds you want to rank for (at first at least).
After you create your campaign you'll be able to check how optimized your page is for each kw.
Hope this helps. Good luck!