Add me in-game, my name is Magdalena! I started playing on JP just a little bit after the news about EN. I'm guessing you've tried out the mission centre on Pold, and played through a few familiar scenarios, only to get stuck? This burned my buns too until I did a couple of the NPC quests, and this unlocked the missing missions.
When the NPC's give you a quest, certain text in their bubbles is in bright green. This is usually things like names of maps and NPC's or a mission the NPC wants you to do. I don't know if you read Japanese, but if you don't, write the green text as best as you can on a sticky note, then look at the pop-up map. You should be able to match a few of the characters and know where to start looking. If this just isn't working for you, vist every map you can and look for whoever has a yellow bubble over their head (you can see it on the area map)
Of course, if you read Japanese, you should probably be helping me with these instead, hehe. I think that once you get past Pold, you don't have to do the quests to unlock missions anymore. (I finished Gald last night without doing a single quest)
Some more hints for this:
Most of the time the target NPC is a guard for one of the villages, or at Pold Base/City.
ランタナ村 is Lantana Village. ラムタ村 is Ramta Village. This can be confusing since they have a lot of the same characters.
Often you'll have to deliver either a letter, or 5 health packs that will be given to you. If an NPC gives you health packs it's not a gift, hehe.
One notable NPC you'll have to visit outside the cities is in the Noburu mountains. He'll need you to gather 10 coal tar.
You don't need to do the kill Nemless quest to advance.
(I'll add a few more location names once I can get back on C21 and see how to spell them)
Oh, and one more thing: make sure to log in on saturday and sunday since you get 3 MT for logging in on those days. You can also buy MT with C$ at the item store.