Query That Grabs Most Recent Date, And Associated Fields

The database I am working with contains several different tables and a variety of information. I need to create a query that accesses information from two different tables. Though the tables contain other fields, the fields I am most interested in are:

Table 1: Protocol Information
"Protocol ID", "Title", "Expiration Date"

Table 2: Regulatory Submission
"Protocol ID", "Description of Submission", "Submitted By", "Date of Submission".

The way the data is stored, each protocol has a Protocol ID, and there is only one record per protocol in the "Protocol Information" table.

However, each time these protocols are submitted to our review board, a log is created in the "Regulatory Submissions" table.

I need to generate a query that pulls only the most recent submission date, so that the query output would look like this:

"Protocol ID", "Title", "Description of Submission", "Submitted By", "Date of Submission" (Where this is the most recent one), "Expiration Date"

From other forums and posts, I tried to create an SQL aggregate function, using Max or Last to get the most recent date. I was successful, but only if the query contained just the "Protocol ID", "Date Submitted", and "Description of Submission" fields. Adding any more, or creating a query to use the outputted data didn't work (it could be that my second query was not written correctly.) I am very novice at creating complex queries, and at SQL.

One additional complication: There are two values in the "Description of Submission" field of the "Regulatory Submissions" table that I am not interested in. They are "Adverse event" and "AE Summary Log". I can successfully filter them out using a criteria expression, but integrating all of these pieces has not been easy (or possible, yet).

I'm out of ideas. This is really complicated, and I apologize. Any assistance would be greatly appreciated.