Please note the following changes are not required for newer DNN installs. New DNN installs already has a high value set for max upload size and longer timeout.
If you're getting timeout errors when uploading the software to your site, you can increase the timeout value by logging in as "Host" on your site and go to Host > Configuration Manager. Select web.config configuration file and increase the maxRequestLength to 18432 kB and executionTimeout to 1200 seconds or greater. You can add the attributes if they don’t already exist in the tag.
<httpRuntime useFullyQualifiedRedirectUrl="true" maxRequestLength="18432" executionTimeout="1200" />