@yesraptors12 you should take a look at this blog to get a perspective on the migration https://business.adobe.com/blog/perspectives/transition-to-adobe-experience-platform-to-boost-your-cross-channel-marketing 

@MYSTERIOUSMAN If the data type of FormSubmissionDate is dateOnly, you can validate using the following expression toDateOnly(toString(nowWithDelta(-7,"days"))) == #{ExperiencePlatform.leadinquiry.experienceevent.at(0)._abc_partner.FormSubmissionDate}

@ngd_11 you can leverage the collection management functions to filter through an array and get to the desired value https://experienceleague.adobe.com/docs/journey-optimizer/using/orchestrate-journeys/building-advanced-conditions-journeys/syntax/collection-management-functions.html?lang=en

@MailySo Did you try the rolling range on the following lines ?   

@Dhanam1 kindly make sure the json structure is matching the XDM schema as that is one of the common pattern we have seen which could possible cause this error.You can download a sample file as described here https://experienceleague.adobe.com/docs/experience-platform/xdm/ui/sample.html?lang=en

@akwankl you can use an extra parentheses enclosing the toString() function to make it work.Example:- 'Test' + (toString(now()))