New to Excel

Hey, I'm new to Excel and I'm still trying to figure out some of the formulas, so I uploaded a couple images of my workbook how I have it set up now. What I really need help with is formulas in my "Sales Invoice" sheet. I'm trying to set this up so that after I input a Product ID and a Quantity, Excel will return the Product Name and the Unit Price from my "Products" sheet in the appropriate cells of my "Sales Invoice" sheet. I've been trying to use LOOKUP, VLOOKUP, and MATCH functions to accomplish this, but I can't seem to get it right. Any help would be greatly appreciated!