METATRON: all you need to do is pick the weapon and some resources of your choice in the menu.
METATRON: you can even preview the results before settling on an upgrade!
METATRON: at your level, you will only be able to go one grade up from the standard starting point, which is always grade F.
METATRON: the player level also affects the equipment's stats at the time of creation, so a grade C weapon crafted at level 20 will start off stronger than a grade S weapon crafted at level 10.
METATRON: quite a clear path of progression, i believe.
METATRON: but enough chit-chatter. why don't you settle on your upgrade?
ARCJEC: XDXD I guess... this one? XDXD