Best I can do for you is say, press and hold on the New Posts button while signed in on your phone. When you realese you should get a quick line that tells you what the button address is and a list of options. IF you go to the New Posts page, open your actions box (the box with the arrow coming out) and you can add that button to your home screen. Problem with that is it will save the current newest post as the newest post always as it's done a search for newest. If you instead hit the copy button you will get the line of text. Then enter the same page again and save it as a bookmark. It STILL will have whatever newest post as the first post you see until you go to your bookmarks menu, find the app, hit the edit button on the upper right corner and paste the actual search string info you copied into the address line of the bookmark. You might also simplify the name. When you save that you will have a direct link that will go there after you open Safari. You probably new that. IF you just use the copy to the homepage button you can press that button on your opening screen and then just remember to press the New Posts button and you will have the newest stuff.
I don't know how to edit apps in the homescreen otherwise we would be home free with one key press.