You should use keywords in your post as well as within your website content. Yes, they should be related to your niche for sure.
Jerome

Write about your niche naturally and once that is done, add keywords that you've generated through keyword search tool. Keywords are used sparingly.

The keywords (which aren't actually single words, but phrases) we use are basically the keys to how we get traffic and eyes on our posts.

By using the keyword tool or jaxxy, you can find keywords that are low competition that can bring you decent traffic over time. If you haven't watched the video on the keyword too, search it in the search bar up top typing "keyword tool" and I'm sure you can find the video tutorial.

The keyword you choose is going to be what the post will be about. If your niche is making money sewing baby clothes you might search for keywords like "ways to make money sewing clothes" or "how can i make money sewing". When you find the keyword that you're happy with that is low competition and brings decent traffic you'll incorporate it into the title of your post and you'll start creating your post around it. :)

I don't think that you need to delete your home page. I think that you have it set up so that your blogs appear there. Try this to see if it helps you.
Go to your back office
Select - appearance
Select - customize
Select - theme options
Select - static front page
Check to see if your latest posted is checked. If it is, uncheck it, refresh your site and you should see the post will no longer be there.
Hope this helps you.
Jerome

You're asking about how to delete menu items. You go into appearance, click the link that says menus. then click "edit menus." Then find the section where it says "pages" and open it. Next, you're going to want to find the item itself, it will be a custom link that says "home." Click "edit menu item," and then "remove." I'm pretty sure that you'll have to confirm, but I didn't go through the removal process myself.

Great question @RGENGANIA you would want to go to your back office and go to Appearance and then Menus, and then again press the drop down arrow on the one you want and then you will see a drop down and then you would moved down some..