What you're looking for is an absolute reference. These are cell references that you don't want to be changed when you fill the formula down.
The best place to start is the video lesson: Essential Skills Lesson 3-12 Understand absolute and relative cell references.
This will explain absolute and relative cell references much better than I could here.
In your specific example, the solution would be to create the formula like this:
By using the $ signs, you're telling Excel that it shouldn't change the reference to cell H1 when the formula is filled down.
You can also go a step further and only use a single $ sign to tell Excel that it shouldn't change the row or column part of a reference but can still change the other part. For example, $H1 would allow the row numbers to increment as the formula was filled down but wouldn't allow the reference to column H to be changed if the formula was filled across.
You can learn all about mixed cell references in the video lesson: Essential Skills Lesson 3-13 Understand mixed cell references.
I hope this answers your question and you're able to create the workbook you need, but please feel free to reply if you need any more help.
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