I took the ICCA cert exam and finished 30min ago. Before the exam I went through the Cloud Foundations material, created account to AWS, Azure and GCP. I practiced the labs on each cloud providers portal and searched info about the topics. The preparation took about two weeks. I have 25 years previous work experience in networking, but cloud domain is new to me.
All in all I have to say that Cloud Foundations material does not cover everything that is needed to know in the exam. To answer some of the questions I would have needed more time to work with the cloud providers portals and get more familiar with the terminology and the products. If you have even some months of work experience with cloud products, I think you are much better prepared for the exam than I was.
Anyway I passed the exam and now I am ICCA certified! In the lab part I scored 4/4, so practicing with the portals did pay off. Overall score was 72%. So, you can pass the exam even without previous experience working with the cloud products, but knowledge of network technologies helped a lot.