How can I fix banner and slide show sizing issues in Studio theme?

[DTunni]

Hello, 

I’m in the process of setting up my store and very new to the world of Shopify, I’ve been watching so many tutorials and reading lots of blog posts but I can’t seem to find how to fix the sizing with banners and slide shows etc.? And if I find solutions they tell you to code it and I have no idea how to even do coding. My issue is I made a banner and a slide show on canva and neither show up right in mobile or desktop view it cuts off the outer edges and I’ve even tried to bring all images and txt inwards to prevent this but it just doesn’t work thing is I can’t find the size of the slide show etc on my Shopify store of what I need to be using when I create the banners etc 

can anyone help.? I may sound extremely dumb and it may be a simple fix so please be kind I did say I was extremely new to this lol 

thank you in advance 🙏🏻