Vlk
2
Hi Tina, welcome to the forum!
Simple questions, simple answers. 
- You can choose any link you want (US or CZ) - both will work OK (and most likely will be able to send data faster than your connection speed).
- You can save it to any location, or you can directly run (Open) the file when asked what to do (Open, Save As, etc)…
Enjoy your copy of avast!
Vlk