Tracking orders on Memberstack

I have 3 different plans that depends on the number of templates a person orders. How can I have memberstack connect to the amount of orders a person has.

Then if a person reaches the limit, a modal can pop up asking him to upgrade. 

My workflow right now is using Webflow's CMS system and connecting it to

Would love some help

(Webflow) Connect # of Form Submits with Membership

We have 3 different memberships. Each one contains a different price depending on # of forms.

I'm using Webflow.

How can I connect the amount of orders a user has placed (a.k.a form submits) to a user's account.

So I can check for an attribute (# of orders), and show a modal that requires a user to upgrade.

Any suggestions?