In your theme settings you should be able to set any page to display as a blog template.
For e.g. when you create a new page, on the right hand said of the page, it should give you a drop down menu to choose the page template like "Full Width, Blog, Contact Us etc. This is one way of doing it.
If your theme doesn't have this option then you might need to set up a sub-domain like
and install wp on that sub-domain and a blogging theme that matches your main website's design.