in this tutorial, we're going to learn basic blending skills: how to blend images with the same color background. first, you'll need two images with the same color background.

I'm going to use this image and this image of Miss Mosh. if you'd like to provide your own, that's fine.
start by assessing the size both your images, before you open up a new image. you'd like the new image, which will be the size of the blend, to be just a little smaller than both images put together. my image is 500x430.
now, open up a blank image once you've decided on the size. paste one of your two images onto the new one, but leave half of it blank, this will be the space for the other image.

now, paste the other image onto that as a selection (ctrl+e), and cover the rest of the blank space. don't worry about overlapping.

promote the new selection to a layer:

de-select everything (ctrl+d) and click on the eraser tool from the sidebar. with your settings, you want to make sure you have a low hardness, and medium size. you can match your settings to mine, or go with whatever makes you feel comfortable:

start to erase away parts of your new layer that overlap ontop of the first. keep doing this until it looks 'blended'

you'll know when it's done when it looks something like my finished product, or one image moves smoothly to the next: