Hello. Where can i write text into custom page? If i choose "page builder", it opens block manager. I dont get this new system

You can choose Manual HTML when creating a page.

I need to write html if i wanna write text into page? wow

Well not really, you can if you want to format it, otherwise it's gonna be plain text.

If you want an "easy way" or formatting stuff, try the page builder, add a WYSWYG block to it and then you have a text editor there.

(Or create a custom block in the ACP set to editor, then drop it in the page)

Aa, now i get this. Thanks =)

You just drag the block from the left over to the page and assemble how you want.