1)how does a hypothesis affect a scientific investigation?
2) detail the steps involved in designing an experiment.
3) what is the difference between an observation and a conclusion?

1)How does a hypothesis affect a scientific investigation?

You hypothesis is your prediction for what you're testing for, so it affects what experiment(s) you're going to do.

2) Detail the steps involved in designing an experiment.

Use the scientific method: Make a testable hypothesis.  Design a study and collect data.  Analyze results and reach conclusions.  Communicate the results.  Replicate the results.

3) what is the difference between an observation and a conclusion?

Observations are small details that you see during your experiment. Conclusion is the big idea that you get from your experiment.