Computer science turned bioinformatitian and AI engineer here. I have a BSc in Computer science since 2002 in 2013 I decided to start a Master in Bioinformatics and Computational biology and in 2018 did a PhD. Since my background is in CompSci, first before I started the master I just bought some popular science books about genetics, and biology the kind of books you see in bookstores like Barnes & Nobles, nothing too specialized. Then watched some videos about some things like Biochemistry, Genetics, DNA replication etc... then what really made a difference is taking a Mollecular Biology course, the one I took prepared me with all the pre-requisites and the book I used in the course are these : Essencial cell biology https://wwnorton.com/books/9781324033356

I feel that this book is clearly written and will give you all prerequisites to continue in a biotech, bioinformatics, computational biology or even biology graduate program if you come from a different discipline.

Good luck!

For genomics, look into viruses, in particular RNA viruses like influenza and HIV. You can fit the entire genome on your screen and learn to read it like code! There are some good text books about viruses that include genomics from scratch (I can't find the one I used now but could look later if you're interested). My advice would be to learn the biology first and understand why we care about genomes before looking into the computational stuff.