i can not get assitant to open on my ipad or computer, i get a message that says not a trusted app developer

iPad - delete GO 4 (which I assume you're talking about), and download/install again.
PC - uninstall, and reboot your PC with driver signature enforcement disabled (google for how to do that), and re-install saying "yes" to any unsigned drivers it queries you about.

But you may have something else happening. Your message is a little confusing (there's no Assistant for iPad).

Hi, thanks for reaching DJI Forum. We do apologize if you are having issues with downloading the DJI Assistant 2 on your computer. If you get a message says not a trusted app developer, you just have to enable the trusted app developer for you to continue downloading. Also, you mention that you are trying to download it too on an iPad but sad to say its only downloadable thru a Mac or a Pc. Thank you.