difficulty creating type and sizing digital image file- also Rogue Monk question

I'm trying to submit my jpeg digital images to a website called Rogue Monk Workshop, but am nearly computer illiterate so following their submission guidelines is proving too difficult. Here are the guidelines:

First, create your artwork submission to the size it should be printed.
Your artwork must be a 300 dpi CMYK file on a transparent background saved as a tiff with LZW compression. Here are the settings for the tiff save window in Adobe Photoshop.



Second, create a small file showing placement of your artwork on a t-shirt. It must be 500 pixels high by 900 pixels wide and saved as an RGB jpeg, png or gif file. You may use our plain colored t-shirts to create this image, but you may choose another solution for showing placement. You are not required to use a background image behind the t-shirt, but you do want to make your submission as attractive as possible. This image is used for voting and is required on the Design Entry Form. You may download a template for this file



Third, create a small file for displaying your design on various areas of the web site. It must be 640 pixels high by 500 pixels wide and saved as an RGB jpeg, png or gif file. The backround color should be the color of the t-shirt on which you would like to see your design printed. This image is required on the Design Entry Form.You may download a template for this file including t-shirt color options


Now I have an older ibook and I have CS4, but these guidelines are near greek to me. Can anyone help?
Also- has anyone heard about Rogue Monk?