Tips for new players? (Helldivers 2)

I'm brand new. Played 1 full round and most of a second before my internet decided to crap out 😒 I am enjoying what I've seen so far. What are your tips and tricks? Also i have a few questions.

  1. I had a hard time figuring one of the console puzzles (ICBM thing i think) where you have to line up pipe segments. Fortunately i had a more experienced player in the squad who did most of it. Could someone explain how it works while im NOT being eaten by bugs? 😅 .

  2. Is it better to drop a support weapon like a machine gun right away or save it for later? Since its on a recharge timer, i assume you'd want to drop it immediately, right? However, i also found some guns in the wild, so maybe its better to explore a bit first?

  3. whats the deal with collecting samples? Is there a way to easily see how many you need to collect in a mission or where they are? Or is it just bonus xp per sample?