None of the answers given below are the absolute truth. Everything you ask for depends on the business rules of each Search Engine, they are just everyday perceptions acquired day by day.
Question 1: In a dynamic website, such as a blog, whenever I create a
post I have to manually index the links in google webmaster tools?
No, not at all. Usually if the domain already exists for some time it already has external backlinks pointed at it. Of course the serps bots will have access to your domain in some way and in the process of crawling your pages you will find the url of the new post. However this can take a long time; if you want to try to speed up the crawling, indexing, and ranking processes, you can use a Sitemap to report new URLs that are popping up in your domain.
Question 2: How do I know when my post link has been indexed on google?
This is simple, just go to google and type: site:http://meudominio.com/pagina
if the result is listed it is because the process of indexing the url has already been completed. However you should understand that indexing and ranking are distinct procedures, the fact that your new page is listed in the SERP does not mean that it is ranked with keywords and receiving traffic.
Question 3: I submit a sitemap.xml, after a few days it is already
outdated right? I have to submit this sitemap with some
regularity or google is scanning so that it stays
updated?
As stated above it does not matter that it has been outdated, at the moment that it has some backlinks, it will run the crawling process across all pages of your domain regardless of which input page you used to access the domain, until the timeout defined by internal business rules of each search engine runs out and it quits. However, the greater the relevance of the domain in the serps, the longer it takes to perform the tracking procedure for the domain in question, and one of the factors that defined domain authority is the internal links of assigned entries and links from third-party sites. These are the famous backlinks.
Question 4: What free tools / software can I use?
What did you mean by that?
Question 5: When talking about betting on a Keyword, how is that? Whenever I post a post do I have to by the same keyword?
No one creates a domain about programming and talks about candy correct? When we talk about betting on Keyword (keywords) is because there is a whole study done around them, to know your search volume, Keyword competition rate, which I defined a mean of how many webmasters compete trying to get the keyword, where the keyword receives the highest search volume, among many other things. Each page of your blog should be dense on the content that is being discussed to demonstrate that the SERPS we define titles with HTML markup are the famous H1 ... H6, in addition the title of the page should contain an abstract description of the subject focused on the words keys worked on the article, among many other things. These combinations of factors is what makes the page a suitor to acquire key words in the serp. However there are millions of approaches to be studied on the web, do not just open a post and write 500 thousand times the same word you want to get, search engines know how to analyze and separate what is a page with dense content and a page practicing spam of tags.
Question 6: Redirect 200? Which is? How to do it correctly?
Redirect 200 ????? This exists !!! I know 301 redirection. Code 200 is the code assigned by the web server to a successful page request, 301 redirects are used for migration of domains or pages of a site. Whenever you want to change a domain name or change the url of a page (post), you must use a 301 redirect, when you redirect a url using 301 the relevance assigned to the source page is passed through the serps for the new url. No damage to traffic you have already purchased. It is an indication of the serps, that wants to change the url that hosted a certain content.
As I said above, SEO is a non-exact science should use not only the above information but also the instinct itself and sensitivity to achieve good positions.
Good Luck!