Post ether & timestamp

First I installed a new WP and then made some posts, great! Then, I imported posts from another blog and they seemed to go in and then when I clicked on pages, I got the famous archive/oops page. So, I tried some things, nothing worked. Deleted installation and all, started fresh.

This time instead of importing, I tried to manually write the archive posts and edit the timestamp. So it seemed to go in and disappear again. My Categories shows that there is a post somewhere by the number indicated, but the post is nowhere or in the ether as it were.

Does anyone have a definitive answer for how to make postings that you want to be timestamped as they originally were and be available and functioning?

Thanks