Separating blog posts into different pages

Ok I am a total newb. Is there a way to post to a page and that post will also show up on a main page? I make a page but I dont see where I can post to that page, just post.

The site will be about cutting expenses. So lets say I have a tab called Home, and then two others, electricity, water. So I write a post on solar power, It shows up on the electricity page and the home page but not water.

Thanks.