I want to create a custom button design

I want to create a custom button design below my demo
button
how can i do that. I’m new in css please anyone help me
Thanks

start with the other shell, you’ll need:
background-color
border-radius
border

if you have that working you can go on with the plus sign part- just make a div or sth inside that fills its parent with only a border on the right side.
After that you have to play around with alignment and the font type to make everything fit nicely.

https://www.w3schools.com/css/css_border.asp