Implement multiple location map in sites with code block

Hi guys, 

I am still a newbie in Squarespace, please allow me to ask:

Does any one knows how to implement multiple location map using codeblock? I tried with the instructions provided by Squarespace, however, it seems that I could not implement iframe code (which is provided by Google Map itself if I wanted to embed the code on my website). It says that my plan only allows html, css...etc and for iframe codes, I will need to upgrade my plan. Is there another way that I can do the same thing without upgrading my plan?

Thank you for your help and hope you have a nice day!