How on earth do I send photos via the new "Photos" application???

I'm using a new iMac. Very fast cable connection (Comcast). The newest software on all Apple products I own (10.10.3 and iOS 8.3). I do not need to update any software.

Now, with that said, I am so incredibly frustrated. How do I email photos using the "Photos" app like we always have with "iPhoto"??

To clarify, I am selecting three simple photos to email to a friend. I have all 3 selected, and then I click on that box (I don't know the official name of the box, but it's the square thing with an arrow pointing up out of it). When I click on that box, *THAT* is where I should see an option to email. But I don't. This is what I see instead:

iCloud Photo Sharing

Messages

AirDrop

Facebook

Flickr

More

None of those options are what I want----I want to EMAIL someone. So I click on "More". Clicking on "More" launches a System Preferences menu for "Extensions". Huh???? Wow am I confused. Anyway, so I sit here staring at the "Extensions" box, and I do see my email program in there (Outlook---I do NOT use Mail). Outlook is "greyed out" and is not clickable. But I do see that Outlook does indeed have a check mark next to it already.

Folks, at this point I am so lost and frustrated I'm ready to scream. I've been a heavy Apple user since 1985. That's THIRTY YEARS! I've never used a PC---ever. I have been Mac all the way, through all of their ups and downs. And it's so frustrating to me that a user like me can not figure out something that SHOULD be incredibly easy.

I would sure appreciate some help so that I can just email photos from "Photos" just like we've always done with iPhoto.

(PS: Yes, I know that I can drag photos out of Photos and plop them down onto the Desktop. Then I can create a new email, and click "attach", and bring those emails into the email. However: 1) That's too clumsy and way too many steps, and 2) It does not allow us to choose from small/medium/large/actual size. I also discovered that I can't even click and drag a photo out of Photos and into an email. It just bounces back. Super, super frustrating!!!!). Thanks for any assistance.