ImportFromWeb is smart enough to detect the best arrangement for the returned data.
For example, if the function is filled with a reference of URLs arranged in a row, it will dispose the values of each page in columns.
Let’s say 3 URLs are in A1:C1, then by calling the function =IMPORTFROMWEB(A1:C1, ... ), the output of page 1 will be in column A, page 2 in column B and page 3 in column C.
On a similar way, if the URLs are in one column and the selectors are in one row, it will create a table with results for each page in rows.
In case you invert the arrangement of the input data, the resulting table will be transposed.
The function will always try to expand in rows and columns as much as it can. You can try to constrain the function by disabling spitResults. As a consequence, if a selector returns several values, it will constrain them into one cell.
The contractStack option can be used to force the function to detect that the target pages share the same type of content, and therefore should be displayed as a long list. it is particularly useful in case you want to display results for multiple pages of search results.