Thanks for those websites!
Watching other players does help me. For one thing, it reminds me that yes, it actually is possible to get a consistently good tone out of a flute, so if I keep at it, eventually I’ll be able to do it too.
Although there are days when I have grave doubts about that, still I can’t deny that I now make those pleasing sounds more frequently than before. Now and then I even have moments where I’ll stop playing and think, Wow I sound really good! 
FWIW, as one who pops in with opinion on occasion - I heartily agree with Jon C’s first response. Get a decent conical flute to start… and while I could conceivably get flamed for this - buy a new one. IMO, used flutes are for the experienced who already have an idea of their own abilities and what to expect from an instrument. At least then, you’ll have no excuses or reservations fueled by the possibility that your used flute might have damages; leaks; or modifications that are hindering progress.
I’m a big fan of Delrin/polymer conical flutes, and ended up with a Rob Forbes that has brought me much joy.
I can’t compare/attest to the all the attributes of larger holed flutes (Pratten style), but I do personally find it much easier to achieve half-holing for sharps & flats along with sliding from note to note with better control. But this is only effective if your fingers are comfortable sealing the larger tone holes to begin with.
May your fluting bring you much joy! Happy New Year.