I need to take a 300 ppi/dpi photo

Hello,

Nice camera :) However it "only" takes pictures up to 180 ppi. You can't change it.

It might be easier to take your pictures as normal and then change their resolution to 300ppi in photo processing software like e.g. photoshop / photoshop elements (commercial) or gimp or irfanview (free).

NB, while it's not going to help here much, you might find this reading interesting:
http://www.dpiphoto.eu/dpi.htm

Hope this helps,

Raf