Open AutoCAD
Type PDFIMPORT in the command line
Select the PDF file
Choose the page or pages to import
Set the import options
Click OK
Review the imported geometry
Save the file as DWG
If needed, clean up lines, text, and layers
If the PDF is scanned, use OCR or trace it manually
If the PDF is vector-based, import results will be better
If the PDF is image-based, convert it by tracing or using specialized software