From the Dashboard page select My Projects in the left side menu

Select the projects you wish to move to a new folder by hovering over them and selected the circle in the top right corner

Select however many projects you wish to move

In the top menu an Arrow icon will appear, click this icon

An Add to Folder box will open with all your folders in it

You can either select and existing folder or create a new one

Then hit Move to Folder in the bottom right hand corner and your projects will all be moved!