You can select two layouts for a portfolio page.

First go to your Admin Panel > Pages > Add new,  you can put any title, in this case "Portfolio".

On the Template dropdown select one of the Portfolio templates:

If you select Portfolio Masonry  you have the option to select how many columns to use.

On the Portfolio Options box you select this:

Also if you have multiple portfolios created, then here you can select which portfolio to display on this page, using this option:

Don't forget to click Publish and that's it, you have a new portfolio item.

Also you can switch to any template layout as many times you want.