In Coda, column headers will pin automatically as you scroll - no special steps necessary.
Right now, it's unfortunately not possible to freeze a column or row in Coda. Reach out to us if you'd like to see this feature added in the future!
Here are some other tactics for optimizing your work with tables:
Move your columns around with a simple drag and drop depending on what you want to work with
Collapse any groups you're not using by clicking the arrow icon