This sample should show you the pattern. You can use Html files wherever I used HtmlOuput objects. I just wanted to keep it simple.
function doGet(requestInfo) {
var url = ScriptApp.getService().getUrl();
if (requestInfo.parameter && requestInfo.parameter['page'] == '2') {
return HtmlService.createHtmlOutput(
"This is Page 2. <a href='" + url + "?page=1'>Page 1</a>");
}
return HtmlService.createHtmlOutput(
"This is Page 1. <a href='" + url + "?page=2'>Page 2</a>");
}
Bear in mind when working with this that the URL from ScriptApp will be the deployed url, not the dev mode url, so if you are experimenting you might want to replace the "/exec" at the end with "/dev".