If you want to include the Meta description and keyword tags to your blogger based blog template, here is how you can do it.
Note: meta tags aren't that important anymore SEO-wise. However, they may show up when data is pulled from a social media outlet like Facebook, so if you do have something there, make sure it makes sense. BUT: It is not recommended. I did a writeup of why.
If you are still set on adding the meta description tag to your blog, here are the directions. The meta keyword tag will be pretty worthless because it is designed to include a string of words that are found on a specific page. Well, your blog has many pages on it, and if you are making this change at the root level, you only get to put in 1 meta description and 1 set of meta keywords in, which most likely will not include what one of your blog pages is talking about.
Log into your blog.
Click on Layout.
Click on Template and Edit HTML.
Make a copy of your code first. Do this by just Selecting All if it (Edit > Select All) and pasting it into a neutral program like Notepad or Text Edit. Try not to use Word, because that will add yuchy stuff to it without you realizing it.
Once you are looking at the code in your Template, find this line at the top of the code:
b:include data='blog' name='all-head-content'/
This line is already there. Leave it, don't edit it at all, and place the meta content code beneath it.
The code you will place will be:
meta content='TYPE YOUR DESCRIPTION HERE' name='description'/
meta content='TYPE YOUR KEYWORDS HERE' name='keywords'/
I didn't wrap these lines of code with the <> symbols because if I did, the code would actually kick in, and you wouldn't be able to see it here. So remember to close your code with the <>.
For your keywords, you can just put a string of words and you don't need commas. There is no need to repeat words in there. That won't help ya.
Once you have entered in the code, click to Preview your blog. This is very important. If your blog doesn't show up or looks funnhy, then you added the code incorrectly, and you need to go get the code you copied and pasted from before into Notepad or Text Edit, and start again. Or, just click Cancel and start again.