As I have seen many of the users are feeling problem in getting there post in a proper order. So , Here I have given a step by step process of how to change the order of your post on a blog. Hope this may help you
Login your Blogger account.
Go to Post.
Click Edit by a post that needs the date edited.
Click Post Options (which is at the bottom of the Compose box).
Finally make the change of date and time as required.
Finally Click Publish Post.
Repeat these steps as necessary so your posts appear in the correct order.
To change your archives to list the oldest post first:
Log in to Blogger.
Go to the Template > Page Elements.
If you do not already have a Blog Archive element, add one now.
Click Add Page Element.
Scroll down to find Blog Archive.
Click Add to Blog.
If you already have a Blog Archive element, click Edit.
Under Options, check Show Oldest Posts First.
Click Save Changes.