How to shell this object?

how do i shell this object? Trying to make leaf blower air funnel but can’t for the life of me figure out if Shell option can be used?

https://support.shapr3d.com/hc/en-us/requests/new

What is the problem to use Shell tool?

I can’t select the front and back faces, only top and bottom halves and then shell does not work on them if i do.

Hide sketches before selection.

Thank you so much that did it! Is there a guide or something to help me understand what my workflow should be, when to uncheck or use sketches and Items pane, etc?

There are a lot of videos on Youtube including official Shapr3D channel. Also you can read manual which available of offsite.