How easy is it to create an online store on Opencart?

Question

opencart

Hello. Can anyone give some advice on how to easily typeset on opencart?
There is a template, I have been making it for 3 weeks already, some moments from the layout design are very difficult, not everything can be done.
Either you can’t set the indent, then it climbs out there, then some other x ... nya.
It's just p .... some kind of c.
Or I'm doing something wrong or I'm stupid.