Learning by my mistakes

I have been entering juried shows.  My entry was almost disqualified because I didn't have the right pixels (ppi).    I am lucky the show chairman emailed me to tell me.  Here is what went wrong:

I am just learning Photoshop.  I was changing the image size to meet their requirements of 900 pixels on the long side.  I wasn't aware that this was automatically changing the Resolution (ppi) to 72 (they wanted 300).

So, I studied Photoshop more and figured it out.  I will put the instructions down here for anyone who is interested:

The requirements for the entry were:  "Resize the image to 900 pixels on the long side.  Set the Resolution to 300 dpi."

Bring up the photo of your image in Photoshop Essentials. (I have #7 - so these instructions are from this version).

After you crop your photo, do this:

Image/ Resize/ Image Size:
My image contained this information in the dialog box:
Pixel Dimensions   19.1m
Width   2208 pixels
Height  3030 pixels

Document Size
Width  30.667 inches
Height  42,083 inches
Resolution  72 pixels/inch

Below this information are three little check boxes with the words...
__ Scale styles
_x_ Constrain proportion
__ Resample image

The constrain proportion should be checked
In my program, Resample image was not checked, but I NEEDED TO CHECK IT.

By checking Resample image, I was able to make the two changes I needed to do:

--change the Height from 3030 to 900 pixels
-- change the Resolution to 300 pixels/inch

I hope this helps someone else who is trying to teach themselves like I am.