how to create slideshow

Using a plugin?

https://www.ads-software.com/plugins/search.php?q=slideshow

Yes, go with a plugin.

Use one that provides shortcode on the usage. So you don’t have to edit the template file, just put the shortcode into the post content area.

Examples

Meteor Slides
https://www.ads-software.com/plugins/meteor-slides/

Responsive Slider
https://www.ads-software.com/plugins/responsive-slider/

I’ve instaled meteor slides, but I can`t make it work. It’s not very clear for me where and what exactly have to write.

The author of that plugin even make a video overview on what it is and how to use it. Do you find it useful at all?

That video alone is a million times better than me or anyone explaining about it in words.