To adjust the width of a column, place your cursor on its right side (to the right of the column letter) and drag to your desired dimension.
To adjust the height of a row, play your cursor on the bottom line of the row (under the row number).
To adjust the width of every column in a dataset, select the entire dataset range and adjust any column. This will update all columns in the range.
To adjust the height of every row in a dataset, select the entire dataset range and adjust any row. This will update all rows in the range.