Free versions floating around the internet are often missing pages, have scrambled OCR text (making them unsearchable), or contain malware. If you type "Erkundungen B2 Kompakt.pdf" into Google and go to a strange .ru or .xyz domain, you risk infecting your computer.
If you are serious about passing the B2 exam within 3 months, download (or buy) this PDF, print out the grammar appendix, and stick it on your bathroom mirror. Start with Kapitel 1 today. Erkundungen B2 Kompakt.pdf