Tables :: Lookup Wizard In Table Design

I've designed a database at work to collate information about locations around the world that are contaminated by conflict and military activities. I'm struggling with the use of the lookup wizard to populate some fields in one table from another table.The database is ultimately meant to be used to identify contaminated sites in various countries and also to be a source of data for an online interactive map. As such, it needs to hold a fair amount of information. I figured that it would be normal that some fields and tables would be connected to one another. So, for example:

Country table is looked up by the conflict table to provide the names of countries participating in a conflict. To do so I used the lookup wizard. Similarly, the Site information table is looked up by the Site contamination event table to provide the names of contaminated sites. The Site contamination event table. Then the Site assessment table looks up the Site contamination event table to provide the name of contaminated sites. The relationship between these three table is intended so that at any given site multiple instances of contamination and their subsequent assessment can be recorded. This is where I started noticing problems. When I tried to input some fields into the Site assessment table, specifically the 'Site name', it would only display the primary and foreign keys in the drop down menu but not the 'Site name'.

- Have I messed up by relying on the lookup wizard in my table design? This seems to be the consensus in this and most forums (I checked another thread in the 'Tables' forum here). That said, I've seen some people making a distinction between using 'Lookup tables' and 'Lookup fields within a table', but given my relative newbyness I'm struggling to see the difference!

- If the answer is yes then what approach should I take to achieve the same aim (having multiple tables that feed information to one another). Initial research seems to suggest putting lookup/combo boxes in my forms. I'm dabbling with that at the minute but so far the results haven't been as desired.

I've attached a zip file with a screenshot of my relationships diagram to give an extra idea. Note that the relationship between the 'Site assessment' table and 'Site contamination event' table isn't showing up as I removed while trying to troubleshoot, but it is supposed to be one-to-many from 'Site contamination event' to 'Site assessment'.