Pete & Welcome to Just Answer,
Sorry I didn't see your question much earlier.
If you still need help with this, let me mention a few "basics" about these system.
First, and probably most important, MOST of the Garmin device do NOT need any "setup" or "installation" - beside simply connecting the device to the vehicle power adapter.
That is, they should work "right out of the box" - once connected to the vehicle power adapter and power is applied.
Now you CAN connect the device to the computer and check updates that may have happened since the device was manufactured, but that is not "required" to get the device going.
Next, when it is time to do the check , Garmin has a program that is loaded on your computer to do that. This program is called Garmin Express, and you should be able to get that program at the following link. There should be a short video on that page that gives you the basics of installing and running the program, and what it can do.Click Here --> Garmin Express
Full Text Link --> http://software.garmin.com/express.html
Also, you are correct in that the FULL manual device is NOT included in the package. This is a common practice in the world today where you only get a SHORT "Quick Guide", and the full manual can be found either on the internet OR included as a file that is stored in the memory of the device (or both).
electronic (PDF) version of the Full Manual device, I have a link below. The manual should appear when you click the link, and can be SAVED or printed from that point.
Click here --> Full Manual
In that manual you will find more detailed instructions about getting the Garmin Express program and operating the device.
As another reference, I have a link to a video that will show you what you SHOULD see the first time you power up the device - to get it set up. You may also see some other videos listed when that video plays, so you may want to take a look at some of those too. NOTE: This is Nuvi 66LMT - which is the same "family" of device as your Nuvi 65LM, so the operations should be the same.Click Here --> Video
I hope this helps. Please let me know if you have any trouble with the resource links I have included or if you have any more questions.Best Regards & Travel Safe, Greg A.(im)