How to fill right with numbers?

That's why I prefaced my earlier answer with the 'vague' comment, since context matters here.

> I'm trying to move a formula over to cells on the right

Move? or fill?

> The cells in the formula should change with each column

I assume you mean that in cell C5 it should reference C3 and C4, D5 should reference D3 and D4, etc... that's fair enough, and should happen automatically...

> When I "hover" over the cell with the formula as you suggested, I only get the yellow dot on the left and bottom of the cell.

The dots 'float' based on where the cursor is... if the cursor is near the bottom of the highlighted cell(s), then the dot will appear at the bottom, so you can fill down. To get the dot on the right you need to move your cursor to the right side of the selected cell - kind of where the dot would be, and it should appear. I didn't clarify this in my earlier post.

> When I selected that cell and the ones on the right, then clicked "autofill" under "Table," nothing happened

Assuming you had cells B5 and C5 selected, the menu you want is Table -> AutoFill -> Fill Right.

This is different from Table -> Autofill -> AutoFill... which will highlight the selected cells and you can drag the border in any direction to fill.

Just for clarity, your screenshot shows you've selected the NEXT cell (C4?), not the one with the formula (B4?)... was than an error in when you took the screenshot? or are you selecting the empty cell.

You should select the cell with the value you want to fill (in this case B4?), since that is the cell value/formula you want to replicate across the column.

Kind of a vague question...

Do you mean with the same number? or with sequential numbers?

Either way, you can fill right via either clicking/dragging, or via menu commands.

How Numbers fills the cells depends on the current value(s) of the cell(s) you start with.

For example, if you have a single cell with the value 1 and fill right, the cells will be filled with the value '1'.

However, if you have a deterministic sequence (e.g. 1, 2, 3, or 10, 20, 30) and fill right, the cells will increment in the same way.

To actually Fill, select the starting cell(s) and hover the mouse over the right-end border of the selection. You should see a little yellow dot appear:

Click the dot and drag right as far as you want... Numbers will extend the sequence to fill the cells:

A second option is to select the starting cells and choose Table -> Autofill -> AutoFill... (Command \ ).

This will highlight the selected cells with a yellow border, and you can drag the border to fill in any direction:

If you want the same number across all columns, just start with the first cell selected and fill from there, or use select a range and choose Table -> AutoFill -> AutoFill Right from the menu (this menu doesn't extend sequences, just fills with the first value).

Does that help?