There aren't resources to practice it but IBM documentation is actually really really good it reminds me of MSDN in the 2000s. So if you can get access to an en

There aren't resources to practice it but IBM documentation is actually really really good it reminds me of MSDN in the 2000s. So if you can get access to an environment to practice the documentation is really solid. It surprises me that you complain about IBM website because you can get everything there, even detailed machine instruction reference for z/Architecture if you want.