Yes i am currently using a macbook air
Same here. I found a few methods to make the signs. One method, for example, is to fill in all four rows with "xxx". Once you get to the bottom row where the Item ID belongs, erase "xxx", and type in the Item ID. Then, up one space, erase "xxx" and fill that in, and so forth. So it should resemble something like;
xxx
xxx
xxx
xxx
xxx
xxx
xxx
Stone
xxx
xxx
B1
Stone
xxx
1
B1
Stone
SkyTheKid1526
1
B1
Stone
Hope it works!