How to make this Google Sheets script dynamic?

I'm working in a script to paste a table on the same sheet, in my code I'm only pasting the table on the row A18

function NewQuote() { var ss = SpreadsheetApp.getActive();  ss.getRange("A18").activate(); ss.getRange('A1:F14').copyTo(ss.getActiveRange(), SpreadsheetApp.CopyPasteType.PASTE_NORMAL, false);};

I want to make this value dynamic and pasting the table on the next available row.