【求助】紧急请教大家投稿须知里的几个问题，谢谢！！

第一次投稿，投稿须知里的几个地方不是很明白，请大家指教，谢谢啦。
1.Supply illustrations at the size they are to be printed, usually 76 mm wide (single column of text) or for especially large figures 161 mm (two columns of text). The intermediate width of 100 mm is also available should neither of these suffice.
这句话什么意思啊？
2. Do not put a box around graphs, diagrams or other artwork.
这个box是指的什么呢？
3. Ensure that lettering is appropriately sized – should correspond to 8 or 9 pt when
printed.这里面的pt是什么啊？我在哪里能修改？
4.给国外投稿，每个作者签名后是不是把签名后的文件扫描，然后e-mail给他们阿？这个签名是不是最初投稿的时候就要签？还是要等到接受了以后再签呢？

谢谢，急等答案。