I am having a headache understanding how and when google indexes a page . I watched this guy's video a bit , and in one of the videos, he says google indexes a page every 2 days but if it notices the updates on your website are slow, it might take a month. Also in the case of unindexed pages it might take longer .Now I have updated the title of my website and also the meta tags, but when google had crawled my site links initially, the title and meta tags were not there. I searched google for my site again and it doesn't show the new and updated title nor the descriptive description. I know google chooses this sometimes, but I have carefully worded my statement for it to show up.So now I want my site to be re-crawled, and after googling and googling I found only one helpful link here : It has the following pointers: Your fetch must have a complete, partial, or redirected fetch status.Your fetch must use the Desktop or Mobile Smartphone Googlebot type.Your fetch cannot be more than 4 hours old.I understand neither of the above. I guess the 2nd point has either something to do with the desktop/mobile drop-down in the dashboard or the robots.txt file. Can somebody explain these pointers please . its all over my head . PS. I can see the following dashboard so far : Thank you. 
Understanding google's doumentation of crawling sites
seo
When Google crawl the web they use a variety of standard automatic custom web browsers that they call bots (short for robot). These bots may not see your web-page in exactly the same way as you do when you use a web browser like Firefox or Chrome. Fetch as Google is a way to see how your pages look to the Google bots. Think of it as viewing the web though Google's eyes.Google prefer to crawl pages on their own schedule.If you want to signal to them that your content has changed and needs to be re-crawled you can use the Submit to Index tool. Please note that I am assuming your question implies that you specifically wish to use the Submit to Index tool (which forces you to use the Fetch as Google tool). Please be aware that the Submit to Index tool is not the only way to achieve the goal of getting your site re-crawled and re-indexed. Industry best practice on how to do this is a much broader question.The Submit to Index button will not appear until you do a Fetch as Google and fulfill their list of criterion. This is to force webmasters to check for and fix most of the common problems that cause crawling & indexing problems for the Google-bots.Fetch as Google is not instant and can take a few seconds to a few minutes.Note that using the Submit to Index tool is JUST a signal to them. There are no promises about how long before they will actually do it.What the criterion mean ...Your fetch must have a complete, partial, or redirected fetch status.This just means that the result they display is the status column when the fetch is done must be one of those words complete or partial or redirected. If you get something else it's probably an error you need to take care of.Your fetch must use the Desktop or Mobile Smartphone Googlebot type.There are 4 options on the drop down listDesktopMobile: SmartphoneMobile: XHTML/WMLMobile: cHTMLYou must only use the first 2 with the Submit to Index tool.Your fetch cannot be more than 4 hours old.The steps are as follows ...YOU click the Fetch buttonYOU wait a few seconds (usually) for GOOGLE to do the fetchWhen done, GOOGLE displays the Submit to Index buttonGOOGLE waits for you to press the Submit to Index buttonGOOGLE adds your Submit to Index request to the database.Basically Google are just saying that step 4 cannot be longer than 4 hours. I would presume that most people press the Submit to Index button immediately but perhaps if step 2 takes a few minutes they might get bored and wander off for a cup of coffee and forget about it for hours and then click it and discover it doesn't work or cause some minor annoyance to the Googlebot.