Thank you! And yeah I didn't mean solder everything including the arduino lol But okay for sure, then I'll solder. And So would you say it's better if I just solder all 4? So that if in the future I decide to stack it'll be possible?
Not only if you decide to stack, but if the shield you're stacking on needs a pin that is on a header you didn't solder - well, that would be a problem, see?
As far as soldering the headers: If these are so-called "long pin stackable headers" - to do a good job of alignment will take a bit of effort. The best way is to put them through the holes on the shield, then stack another shield on top, and flip the whole assembly over. Make sure the shield to be soldered is flush and even with all of the header plastic, then solder the two end-pins of each header (they can just be a quick tack solder joint if you want), then pull off the shield you used for alignment. Place the shield you are soldering upside down on a flat surface, and finish all solder joints.