I can't get Tags and Archive pages to appear Necessary disclaimer. Web design dilettante, so I ll probably have trouble following your answers if they get too technical. 

I am building a blog. I am am trying to use tags bellow posts and when the user clicks on them, go on a page that shows all the relevant posts containing that tag. 

I followed the instructions on this page and while I can get the tags bellow the blog post, when I click on them, I am getting a 404 page. 

Similarly, I tried creating an archive page by following the instructions on this page but while I can get the code to appear if I append it at the end of my index.html page, I cannot get it to appear on a separate web page. 

I suspect I am making a blindingly obvious mistake, but I can't figure out what. Do you have any suggestions of things to try?

Thanks
Sounds like you are missing a few tags, which we can fix when you post your code. Meanwhile, if you can spare the time, checkout Mijingo.com Craft Essentials, it's like being in the matrix as within one day you'll know lots about Craft!

It will safe you lots of time figuring out the basics....