Opportunity valuation rule (Check Syntax) is showing:Error incorrect argument type for function (ISBLANK)

I have no this module since yesterday I need help

1️⃣ CRM Fundamentals – Understand how Salesforce helps businesses manage customers, data, Security and processes. 2️⃣ Core Admin Skills – Be confident with Objects, Fields, Reports, Dashboards, and User Management. 3️⃣ Business Mindset – It’s not just clicks—it’s solving problems. Learn how to translate business needs into Salesforce solutions.

Before I could even introduce myself, everybody already knew me… like, is my face ChatGPT or what?!😂😁😁😁🤣😂😂😂 Guys Guess who ate the highest chicken yesterday 😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂

This is the beginning of my assignments by for the sake of my laptop I can't download it. I have taken my whole night doing this assignment @Godwin Mbah pls come and show me how I can download it.Thank you.Good morning