So I just got into Warframe this week, having a lot of fun after getting through Earth, Venus, and Mercury, but I'm now faced with needing to go to Mars. The trouble is, Cetus and the Plains of Eidolon are between me and the junction.

Until now, level progression has been pretty obvious and straightforward, but I walk into Plains expecting that something obvious will be there for me to do to progress through to Eurasia (and thus Mars Junction) but... nothing. I get grouped up in Plains and it's a big open space with zero guidance as to what I'm supposed to do. I shot some big guys, spent a little time taking out a camp, and backed out, assuming that I only needed to visit. But Plains & Eurasia are still locked, and I have no idea what I'm supposed to do now.

From reading some other threads other new players are similarly confused. Apparently I need to do a 'bounty', but I have no idea what that is or where to do one, the game has certainly hasn't told me anything about them.

Am I missing something obvious, or is this bad game design for new players?