If you are interested in some rules in Perfect World, you can read the following tips gotten from other websites and get the main points you need.
First, you can send your Calendar design by 6:00 P.M. (pacific time) on Monday, June 1st.
Secondly, please do not resize the dimensions of the background template (you need it to fit on standard monitor sizes!).
Thirdly, designs must incorporate a calendar grid for the month of June, along with the PWI logo and/or the URL of our website.
Fourthly, Files MUST be in .jpg, .gif or bitmap (.bmp) only.