I could have sworn we talked about Faraday Cages before. First, there's the U-toob video showing how to make one using a metal garbage can and metallic tape. Works well and is large enough to put in radios, laptops, and other electronics.
For smaller stuff like cellphones I use the metal tins that they sell with Christmas cookies and fruitcakes. You can find them in a variety of sizes and shapes. Seal the seam with the metallic tape and you have something that will hopefully survive the blast.
I have one that I keep a spare condenser and voltage regulator for my '37 - she'll be running when everything else is dead as a doornail!
The E&M wave front can sometimes be so strong that currents on the outside surface of the cage can induce a new E&M front on the inside surface. to truely harden against such an event you need multiple layers.. So that trash can in a metal building, and smaller contents inside wrapped in a conductive foil...
The more layers the better.
But remember that two weeks after the first attack, another may come and wipe out the stored stuff and you will probably still have no news at all of what happened, ot why . ...Real EMP attacks are very difficult to prep for.
One layer is probably enough to survive a Carrington event - depending on intensity and which side of the planet you are on an how long the event lasts.