To keep an area of a worksheet visible while you scroll to another area of the worksheet, go to the View tab, where you can Freeze Panes to lock specific rows and columns in place, or you can Split panes to create separate windows of the same worksheet.
Working with a massive data set in a spreadsheet can be difficult, especially as you scroll up/down or left/right and the rows and columns may be hard to track. There's a simple trick for that if you've got a header row or column, where the first row/column has a descriptor. You freeze it so when you scroll, that row and/or column (or multiple rows and/or columns) don't move.

Freeze the first column
Freeze the first two columns
Freeze columns and rows
Example: If you freeze the panes around cell C4, rows 1-3 and columns A-B will be frozen as you scroll as shown below
