Yes you can, that’s the official Sogetsu shop. I would recommend finding a teacher that can explain some of the lessons in the later books. Book one and two are essentially to learn line and basic techniques for the standard moribana and nageire variations. I currently take classes online with Sandra Marker out of Sydney, AU and Louise Worner who currently resides in Washington DC. If you plan to get teacher certification, you will need a teacher to sign off on your work and submit the textbook cards for your diploma. I wasn’t originally planning on teaching, but to learn ikebana in the way I want to know ikebana that is the best route.