The most effective way to learn these rules isn't through dry memorization, but through contextual application. A "Grammar in Use" approach pairs a clear explanation on one page with practical exercises on the next.
An A1 PDF must start here. It should include: russian grammar in use a1 pdf
Open the PDF on your phone. Read a grammar rule, then immediately close your eyes and explain the rule to yourself in English. If you hesitate, read it again. This builds automaticity. The most effective way to learn these rules