Test instructions modal

[darakhshanda]

User story

As a new user, I want clear instructions on how to use the typing speed test so that I know how to start and complete the test.

Acceptance Criteria:

[ ] Clear instructions on how to take the test are provided on the homepage.
[ ] Instructions are easy to understand and follow.
Tasks:

[ ] Create a modal that displays clear instructions to the user on how to take the test.
[ ] Add a clearly visible button on the web page to open the instructions modal.