You should be asking your instructor these questions. If they don't know the answers, you should consider another CAD school. Of course, I would suggest Nash Community College, which has an online program that you can take from anywhere in the US.
I'm not crazy about using US paper sizes with mm drawings but you have three choices. 1)Scale your model space objects down by a factor of 25.4, which converts the model to inches and change your dimensions to scale measurements by 25.4 which would report distances in millimeters or you would need to keep the model in millimeters; 2)Save the drawing as is and insert it into another imperial, which should automatically shrink the drawing due to the insunits settings and setup the paper space in that drawing by cut and paste from your current drawing; or 3) do the following:
- Set insunits to 4 (millimeters, since your block is in millimeters.)
- Use -dwgunits to set the drawing to millimeters. Most of the other prompts should be answered yes but since your block is already in millimeters, you don't want to scale the model space.
- In paper space, you need to use pagesetup. Choose the general documentation PDF printer. Choose its properties and add a custom paper size. Choose start from scratch and choose millimeters. The size of the current letter shape should be automatically converted to millimeters. Save it and select that as your current paper size. Then set the scale to 1:1, the units to mm, and what to plot as layout, temporarily. Close the page setup.
- In paper space, scale all objects about 0,0 by 25.4.
- Zoom extents in each viewport to correctly center each view. Change the right view viewport from perspective to parallel (right click on the viewcube). Set all viewports to 1:5 and you're good to go.
I try to avoid assigning a millimeter plot on an imperial sized sheet like letter. ISO sizes are A0-A4. They are also built into the acadiso.dwt template, which is what you should have started the drawing with.
If these concepts are confusing, ask your teacher or sign up at https://online.nashcc.edu/ for ARC 114, which begins in Fall Semester 2019. First class is Aug 15.
Architect, Registered NC, VA, SC, & GA.