Grr, sorry had something posted but my mouse is acting up and deleted before I realized it...

Your ReseachT would be your main table in this instance. In comparison to Richard's TechHelp videos, think of it as the OrderT. It would contain basic information about the research you are doing.

ResearchT:
ResearchID autonumber
Description short text
Notes long text
.... Any other fields that relate to the research in general

EraT
EraID autonumber
Description short text
Notes long text
.... Any other fields that relate specifically to an era

ResourceT
ResourceID autonumber
Description short text
EraID number ---- foreign key to the era table where it is found
.... Any other details related to a specific resource

ResearchDetailT
DetailID
ResourceID
Qty number - type long or double
Notes long text
Any other fields that tell you what you need for each resource for a specific research

Donald
Here is a list of all the tables I have:
Era Table- Where the research is located
Origin Era Table- Where the resources come from
Research Name Table- Just the name of the research and the EraID as a foreign key
Research Data Table- ResearchNameID (foreign key), ResourceID (foreign key) and Qty Needed
Resource Table- Lists all the resources needed including those needed for other resources.
I hope this helps.

Do you need 2 Era tables? Do they contain different types of information? If they are the same Era's or, even if different, if the type of data is the same, you could just reference the EraID as appropriate in each table. If there are different types of Eras, you could have an Era Type field.

In any case, you might have an EraID in each table, if for instance, a resource becomes available in one era, then that resource may be combined with other resources to form a new resource in a later Era, and then all resources get combined to do research in yet a later Era.
Other than that, I would liken your system to Richard's Order Entry system:

Research Name Table - similar to OrderT describes the Research - EraID shows up when research becomes availableResearch Data Table - similar to OrderDetailT describes the "Products" needed to complete Research
Resource Table - similar to ProductT in that it contains details about Research Items

I might add a "Component" Table or something similar which contains the breakdown of each resource item that goes into each resource

Richard does something similar when creating product bundles in his course... You may sell a computer but the computer has a case, a hard drive, a monitor, etc.

A very general version might be his Groups video. He also does Food/Meal Groups in his Fitness Series starting around Episode 3. More detailed explanations come in around Access Developer 25

Sorry, this onion has so many layers, I kept going in circles trying to explain it. Hope I didn't confuse you worse.

I posted a picture of what I wound up doing for the information i needed.
and yes i needed separate tables for Era because one is the Era that the research comes out of and the other table for Origin is where the resources come from. Yes they are the same but when i start inputting the data for the research I dont want too much information in the Era table. The first Era table is like the customer table and the Origin Era table is like an Employee table. They have the same information but they do different things.

In the table picture i just posted it shows up how i want it to. The Origin Era with all the related resources from that era and then it lists the resource(s) needed to make that specific resource.

Actually, as you progress further through Richard's courses, you'll learn that it is actually better to make one table for multiple things, for instance, customers and employees. They are both holding person/contact information. You just add a field that identifies whether they are a customer or an employee if needed. Sometimes, a customer may also be an employee and vice versa and having separate tables would require duplicate maintenance of information which increases risk of errors or faulty data.

As for how you have it laid out above, you could easily make a form for the Origin Era that collects the name of each era. Then in the footer of that form, use a sub form that lists all the resources within that era, in the footer of that subform, another subform which lists the additional resource items that match that resource. And, finally, in the footer of that subform, another subform which lists the additional resources that additional resource requires. Similar to the technique that Richard used in his Multiple Cascading series.

Alternatively, you could use list boxes instead of sub forms then just double click the resource in the list box to open that resource.