How to manage data in wordpress?

After playing with many plug in modules in WordPress I have come to the conclusion I need to understand best practice around data better. I have read about custom post types and meta and taxonomy etc. I have yet to find a good high level overview of what my best way is to gather and display data the way many scenarios need it. Please help me understand this starting with 3 random data types.

Product
Location
People

Each of these top level data types will usually have numerous fields associated with them. The information for each will need to be collected independent of each other. Someone will enter the product and all the fields that describe the product. Someone else will enter all the locations the product will be sold at. Someone else will enter all the people that know how to sell each product.

Lets next just look at the data entry portion. Whoever is entering the people will need to select what location the people will work at. They will also need to select what products that person is familiar with. The form that is used for entering people will need to allow them to have fields as part of their entry that pulls a select-able list from both product and location. The same scenario could exist for entering the location information. Each location will need people selected, product, etc.

Now it is time to display this information

Lets say I want to show a page with a specific person, the address they are at (field in the location area) and 4 different products.

I was looking at this as 3 different custom post types. It was difficult to figure out how to get one post type to pull info from another when populating data. We do not know PHP. Hopefully there is an easy way to do this.