***new here*** need bigger ferret cage

I've got 3 ferrets 2 male, 1 female all spayed and neutured. The only problem is i need a new ferret cage. Any one know how to build a big ferret cage?

my friend bought a garden shed and covered the bottom in newspaper and sawdust/woodshavings and a little box with a blanket 4r a bed and then just let them out in the run that she bought out the pet shop when it wasnt raining during the day but she had quite afew ferrets but i cant remember how many b/c she moved to austrailia and i have lost contact with her