Buy a used physical copy. The tactile experience of flipping between the diagram on page 124 and the formula on page 126 is superior for learning retention.
Many technical colleges offer e-book access to students.
Use the PDF search function to jump between related topics like "modulation" and "detection." Where to Find the PDF
Use Mithal for basic concepts & problems, then supplement with Kennedy for broader understanding, and finally move to Hayward or Pozar if you pursue RF seriously.