Resize spreadsheet android

Hello all, I'm new here. 

Please help me with some basic tasks in Excel for android.

I have a grid I'm making and I need to resize it to 5 inches tall and 7 inches wide. For some reason I can't figure out how to resize the whole grid in inches. 

Also, I'd like to add a small up arrow shape in some cells and an equal size down arrow shape in other cells, equally centered in each cell. But when I add the arrow shape in Excel, it inserts the shape outside of the cells, and I can only try to manually move the shape to the general center of the cell I want it in.

Basically, I am making a sports parlay card for fun, and I want to have a cell with the letter "A" followed by an up arrow (to bet a game goes over the total) and a cell below it with the letter "B" followed by a down arrow (to bet a game goes under).

Can anyone please help? Thanks