xTypo button is not working properly on my website.

It's very easy to create a new theme. You just need to create folders and files with stucture like this :

-- name_of_theme (folder)
---- assets (folder) ---> place for any assets of your theme, such as images, fonts etc
---- index.html ---> create a blank html file to disallow directory listing
---- style.css ---> your xtypo css rules

then upload them to [joomla_root]/plugins/content/xtypo/themes folder.
The name_of_theme will be automatically detected in the backend settings. It should be also upgrade-save when the new version is coming in the future but I'd recommend you to always backup your xtypo theme

To make it easier to start, you can duplicate any of folder under the [joomla_root]/plugins/content/xtypo/themes (bootstrap,darko,default,greychatter .. etc) and rename it with any name you like.

Make sure you have copied any file/folder inside of assets folder to the assets folder of your active theme. For example both of darko and lytocolora have their own fonts folder inside the assets folder :
[joomla_root]/plugins/content/xtypo/themes/darko/assets/fonts
[joomla_root]/plugins/content/xtypo/themes/lytocolora/assets/fonts

That's ok. both of fonts are identical