Now I understand you better. First, I haven't heard of the term purple team.
There is Red Team -- Offensive Security, and Blue Team -- Defensive Security.
It all comes down to what is your knowledge level in networking CCNA R&S style, basic computer OS knowledge, and it wouldn't hurt programming knowledge skills as well -- Python, Bash.
If you don't have any networking knowledge, I would recommend either studying Cisco CCNA R&S or the CompTIA Network+
For the Info Sec realm, I would recommend the new release course here on ITPro.TV called Cisco CyberOps Associate (200-201)
very good course for beginners, I love this course.
I also recommend, the CompTIA Security+ the new version. CompTIA CySa+ this will give you more than enough knowledge on the Blue Team side.
For the Red Team side, you can study for the CompTIA Pentest+, CEH V11 (is releasing soon here) and if you really want to master your PT skills, and you definitely should, go for the Offensive Security OSCP course, that is a pure practical hands on exam. You must know Linux and Python for the OSCP exam.
It looks like overwhelming and very intimidating to tackle all of this at once, but this is the only path to truly master your skills you will need in the real world...
Good luck in your studies, and take it easy one course at a bite and very soon you'll be a master on the keyboard :))