Two possible meanings. Do you mean:

1. A guide about everything regarding soft cheese? (as in 'a guide to Kuala Lumpur' = 'Buku panduan mengenai Kuala Lumpur')
The translation would be:
'Buku panduan mengenai keju lembut' or 'Panduan mengenai keju lembut'

2. A guide to making soft cheese?
The translation would be:
'Panduan membuat keju lembut'

I hope this helps :)