Clarify actions performed by eksctl

[tucktuck9]

Clarified what actions eksctl performs on the user's behalf, based on user feedback.

Issue #, if available:
N/A

Description of changes:
Users expressed confusion on the actions that eksctl performs on their behalf:

• Clarified in the description what actions eksctl performs
• Incorporated the sample value descriptions (long line of "replace x sample value") into the description
• Condensed the verbiage overall and moved the install command to the end of the paragraph

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