Shift+Down Arrow not working to format text in multiple cells

I am building a glossary of terms in a table and want to format text in multiple cells (i.e., font size and bolding). All online research indicates that I should be able to 1) highlight text in a cell, 2) hold down SHIFT, and 3) use the down arrow to select text in other cells. I have even seen GIFs of this being done.

Whenever I try this, the selection highlighting in the first cell disappears and the selected cells' borders are highlighted. Rise 360 then only gives me the table formatting floating toolbar, not the text editing toolbar.

I feel like this should be an easy task, but I have spent far too much time and energy trying to make this work. Can anyone offer guidance or explanation?