upgrade 1.3.8a to 1.3.9c

Hai ,
I just want to upgrade the zencart 1.3.8 to 1.3.9 . I just read some links says that the /docs/2.readme_how_to_upgrade.html file said the up gradation steps. But i can't understand this document saying that upgrade from that version to another version or previous version to that version . Simply say i will follow wich documentation 1.3.8 or 1.3.9 when upgrade 1.3.8 - 1.3.9

please help me :flex:

Why upgrading your 1.3.8a to 1.3.9c and not to 1.3.9d (the latest version)?

In your** zen-cart-v1.3.9d-full-fileset-06032010** there is a file called 2.readme_how_to_upgrade.html

Follow the instructions of this file step by step.

Thanks :clap:

Hai,
When i upgrade my site previous data in the database how can insert new database .
Please help me :clap:

Hai,
The part of the upgrading process i found the changed file using the winmerge software . Can i add these files directaly in to the new version (1.3.9d) folders before the installation
plz help me:flex:

depends on the changes. the changes affecting looks is possible to just change. any programming changes require some thought on the merging as there is some logic to be upplied. as in the changes have to be carefully done. this will happen if you have modified the site before upgrading
im new to this, someone check what im saying