The Record Date is when the club has to actually own, and be holding the stock, in order to receive a dividend. The Ex-dividend date is the date on which any new purchases of the stock will not be on record in time to receive a dividend.
The Ex-dividend date will be no less than two business days before the Record date.

The reason these dates are used is because in the current market, when you Buy or Sell (Trade) a stock, that company's books must be updated (Settled) within three days of the transaction. This is why your broker might show a Trade date, and then a Settlement date on their records.

To give an example of how all these dates work together if you are planning to buy a stock:
Let's say you know that the Record Date (Date of Record) for a stock your club is interested in is on Thursday of a given week. Assuming the company follows a standard procedure, that means the Ex-dividend date will be no latter than Tuesday.
This means that if your club has been thinking about buying the stock, the broker would need to make sure the transaction (Trade Date) is no latter than Monday, in order to make sure that the Settlement Date comes on Wednesday, BEFORE the Record Date of Thursday.

Now, how do they work when selling a stock?
According to the IRS (https://www.irs.gov/publications/p17/ch14.html)
The important date for tax purposes when it comes to selling is the Trade Date. While the Settlement date may be the date the broker uses to show when money or shares arrived, the Trade date is the one to keep in mind when checking for long or short term capital gains.