A good tip for soldering those SMD's is to put solder on one pad, solder on the smd to that pad and the solder the other side having the other side already stuck on the board.The temperature i used is 650 f. SMD soldering is difficult but a complete noob can do it, i did, just watch some YouTube videos tutorials, the one that helped me the most is done by a guy by the username of Whitefiredragon.
But like pkircher said that crusty stuff stuck on the pcb is flux and it will come with isopropyl alcohol, the higher the percentage the better, i used 93%since that is what i have.