IMPORTANT STEP! When you first sit down to operate after someone else has previously operated, go to the N1MM logger and press CTRL-O to change operator, then enter your callsign. This is critical so we can tell who was operating that station for a given set of contacts. This will need to be done anytime you change stations or anytime the operator changes. Please note that the contacts you make will be made as K9IU (Kilo Nine India Uniform), not as your personal callsign. This step is done to make sure we are legit with our logging.
Simple, enter the callsign of the station you are looking to log. If it is a duplicate station, you will see red lettering saying "Dupe!". If you are hunting for contacts it is always a good idea to enter their callsign before making the actual contact to check for a duplicate contact on that band. If this is the case, move on to the next contact. Otherwise, make your contact with that station, and record the signal report and exchange received. In the screenshot below, the previous contact logged shows up in gray lettering (C06MT) while the current contact being logged is YV1JGT. This example falls along the rules of the ARRL DX SSB contest where the exchange we are expecting is a power report (1000 in this example). Our sent exchange is always Indiana and a signal report (59), so the Indiana portion is hidden since it will always be the same. To save time, use the Tab button to move between the entry fields. Once these details are entered, just hit "Enter" to log the contact and move on. You don't need to worry about all of the extra buttons and options on the N1MM logging screen.

Other things you should know about N1MM
In many DX contests, the DX stations will operate in what is called "split" mode. This means that the station is listening on a different frequency than they are transmitting on. One reason this is done is due to different band allocations in different regions (a DX station may only be able to legally transmit on a frequency that we are only allowed to transmit digital signals from here, so they will listen for our signal in a frequency that we can legally transmit phone). It is important not to transmit on the frequency that the DX station is transmitting on when they are operating split! The best way to find out if they are operating split is to listen. If you do not hear a pileup on a DX station that is coming in strong, chances are the pileup is on a different frequency. The DX station should announce where they are listening when they call CQ but in some cases they only do so occasionally so you may have to wait to find out where they are listening. For example, on 20m, a station may be transmitting on 14.130 but announce that they are "listening 230" meaning that they are listening on 14.230. They may also say "up 100" which would mean the same thing. Another way to find out the split frequency is by checking comments on DX cluster, like at http://dxsummit.fi (if this station has been spotted on the cluster, sometimes they will note the split). Know ahead of time if the use of the DX cluster is against contest rules or changes our submission class in any way. Usually we submit as a multi-op station which includes the use of DX cluster. On the other hand some people feel strongly against the use of DX clusters in contesting.
See page 47 of the IC-746 manual by clicking here. (this will be PDF page 49)
See page 23 of the TS-570 manual by clicking here. (this will be PDF page 29)