Hi Ed Jobe.
If you want a sheet size that is 24X36, Open the standard drawing file form open pull down menu. Delete sheet 1 in the browser(rmb -> delete). Go to Insert pull down menu and select Sheet and select custom size in inches then type in the size 24x36. Go to drawing resources in the browser and rmb click and select Borders and Insert drawing border and click OK. Now, go to Format pull down menu and select Define new title block and sketch your title block with sketch tools or insert autocad drawing. Exit from sketch mode and save as any name you like. Then click the + sign in front of title block in the browser and pick the name that you saved the sketch as and rmb and select insert. Now, rmb on the sheet and select edit sheet and give a name for your custom sheet. Now save this file in the template folder as your custom sheet.