Slideshow and text

I want to have a section with on one side a slideshow and on the other side text.
I cannot find a current section that has that. Is it possible to create it myself?

Use a summary block to create the gallery on the left, you'll need to link it to a collection like a blog.

I only want one photo to appear and that you can click like a slideshow. I don't find that option in your solution? And if possible, I don' want to create an extra page fot the photo's. I preffer tot insert them like in a gallery.

If you are a Circle member you can access the old gallery block, but it's usage is not generally recommended for Fluid Engine as it was designed for the previous editor. You could join or ask a Circle member to add this for you...

Or can I place 2 sections next to eachother in SQ?

You could use this technique to place sections next to each other: 

https://www.will-myers.com/products/p/build-grid-page-layouts-in-squarespace-workshop