This is a series that should help you understand how Czech grammatical cases work. When Czech people learn cases at school, they also learn so called “case questions” = forms of the words WHO (kdo) and WHAT (co) belonging to each case. Learning these forms is important because you’ll need them when you want to make questions, but learning them will also help you learn the declensions of adjectives and pronouns later.
If you want a useful declensions handbook, you can buy my publication “Pocket Czech Declensions”.