After you click Upload Photos from the right hand side of the
Gallery heading, go to the blue Forum section and carefully read the instructions. In reality it isn't as complicated as it sounds.
Take particular note of the image size information and, if necessary, resize your photos with suitable editing software before continuing. Something around 800-1200 pixels by 72 or 96 pixels (even upto 120ppi) will work fine.
Then just follow the instructions, choose a suitable folder from the choices given (unidentified birds) but don't forget to add a name to the images.
When uploaded; probably the easiest way to transfer them to a post is to click the (Image Library) link on the right side (just over there in blue). When your images appear, click on them and close that viewing area. Your photos will automatically be linked here.
And, of course, if you get totally lost just ask directions once again.
Hope this helps.
Geoff.