Simply you can make test plan .Test plan than test scenario.Test scenarios than test cases.
TEST CASES:A test case in software engineering is a set of conditions or variables under which a tester will determine if a requirement or use case upon an application is partially or fully satisfied. In order to fully test that all the requirements of an application are met, there must be at least one test case for each requirement unless a requirement has sub-requirements. In that situation, each sub-requirement must have at least one test case.
TEST SCENARIO:
Scenario testing is a software testing activity that uses scenario tests, or simply scenarios, which are based on a hypothetical story to help a person think through a complex problem or system. They can be as simple as a diagram for a testing environment or they could be a description written in prose. The ideal scenario has five key characteristics. It is (a) a story that is (b) motivating, (c) credible, (d) complex, and (e) easy to evaluate. These tests are usually different from test cases in that test cases are single steps and scenarios cover a number of steps. Test suites and scenarios can be used in concert for complete system testing.
TEST SUIT:In software engineering, a test suite, also known as a validation suite, is a collection of test cases that are intended to be used as input to a software program to show that it has some specified set of behaviors. Test suites are used to group similar test cases together. A system might e.g. have a smoke test suite that consists only of smoke tests or a test suite for some specific functionality in the system.

A test suite often contains detailed instructions or goals for each collection of test cases and information on the system configuration to be used during testing. A group of test cases may also contain prerequisite states or steps, and descriptions of the following tests.

Collections of test cases are sometimes incorrectly termed a test plan. They may also be called a test script, or even a test scenario
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