Unfortunately, Realistic doesn't include any shortcodes by default. It's easy to create them using mainly Bootstrap components but Realistic is based on MDL https://getmdl.io/
so you need to use MDL components instead. Check this page for more info: https://getmdl.io/components/index.html
You can add the components HTML directly to your posts but the use of shortcodes is better because it keeps your posts clean.
The homepage shows just recent posts. Can I customize that like Redwaves theme?
RedWaves (premium) has a lot of shortcodes mainly needed for included Page Builder. That's how the fancy homepage is created. So to create a similar page on your website, we need to port all those shortcodes to Realistic and make them compatible with it which is beyond the scope of our support.
How can I get the sidebar like the Redwaves theme. I mean sticky sidebar while scrolling up and down?
I am using a jQuery plugin called Theia Sticky Sidebar https://github.com/WeCodePixels/theia-sticky-sidebar
but there is a WordPress plugin based on the same jQuery plugin. You can get it from here https://wordpress.org/plugins/mystickysidebar/
If I have to upgrade the Realistic theme without migrating to another theme; how can I do that?
Usually, an upgrade of WP theme is just another theme with a different ID and more features. So if there will be a premium version of Realistic, it will be a standalone theme (I will be working on a premium Material design theme in the future but it's unlikely to be an upgrade for Realistic. The main reason behind this is that Realistic is based on MDL but the other theme will be based on Bootstrap Material Design just like the main website Themient.com and this forum. It's obvious how stable this framework is compared to MDL.
I am ready to buy a pro version of Realistic (if there is one) but not willing to change it because of certain obvious reasons.
There will be a premium Material design theme from me but more likely under a different name but it will share the same design as Realistic including the cool animations like the ripple effect. But I have to release Elif first. It's been under development for a whole year and now it's almost complete. I have to say that development was discontinued for few months because I had to work on RedWaves v3.0. Also, I had to redesign Themient.com from scratch and this forum too.
Working on the upcoming material design theme will be a lot faster because now I have a good library of code that I can use in future themes.
I promise you I will do my best to deliver a premium material design as soon as possible while keeping Realistic maintained but unfortunately, I cannot provide a specific release date.
I think there is a world market for maybe five computers. - IBM chairman Thomas Watson, 1943