To free up space in this new Android update is very easy

First go to Settings > Storage.

There is new tool in this named as Manage Storage at the top. You will see Smart storage which when you toggle will remove backed up photos and videos when the memory is full.

If you get Free up now you will get more specific options for removing the stuff from your phone. It also gives you lot of suggestion if you want to delete the unused items

You will also get the detail of the most storage using apps so you can delete them if you do not need them

From the shared storage menu you can touch on any of the categories e.g. apps, images, or videos. In this way you will come to know which app is using more storage. You can also touch the overflow menu and go to Free up space if you directly want to free up storage