Can I use done HTML/Template with edits?

So I was wondering is this legit? Like I copy/paste scratch of code (to not code from scratch) and to change all text and some pictures and to design site, but not from scratch.

 

Not sure if I understand you question correctly, but you can use php includes and call pieces of code into your content. For instance, you create a page with text only and call your template as header and footer.

 

Well I dont know very well css, so I will use css from other sites, is that allowed?

 

your question is not so clear:
if you are talking about the content changing then you create a database and by php code u can have diifferent content with single website
there are lots of free templates available you can use it and edit it .its easy

 

If the template coder allows you then you can change the code.
If the template is released under GPL licence then you can use the template as it is but changing it is not allowed.
If you are self-respecting web-designer then probably you will not steal any code and show it off as your own. However, you can get and Idea from that template and create a new one.
Its always difficult to convert the theme than the creating new fresh one.

You may proud that it is fully created by you