Loading the profile depends on your OS, if it is Win 10 then yes all you need to do is double click on the profile. Alternately you can just copy the file to C:Windows/System32/spool/drivers/color/. Should you need to remove a profile from your system, just remove it from this folder. Removing it can be useful if you want to update a profile for any reason. The lab I use regularly issue new profiles, so being able to remove the old ones is useful, otherwise you do tend to have a job to know which is the correct one you should be using.
Once you have installed the driver in the OS it will be available in Lr. I will usually go to Proof Colours in Lr, and select the profile for the paper. You will probably have to use other to find the printer profile that you need, once you have selected it they usually end up as sticky on the list. I also chose to create proof copy at this time too. The Proof copy will be a normal VC, just with the copy name set to the profile. With the proof copy I will then do the minor edits that will be required for the print, for example setting the crop ratio to match the paper size you are using. You might also want to bring any Out of Gamut colours back into gamut using an appropriate tool.
Once I have the print cropped etc then it's time to move to the Print module. I normally set the printer driver parameters as a first step, with colour management turned off, which varies by brand/model, as the first thing to do. For a third party paper manufacturer I will then set the other driver settings, such as paper type and print quality settings based on the settings recommended by the paper manufacturer. The high end papers such as Red River should have detailed information available for these settings with the colour profile. You also have to set the paper size at this point, since the Print module uses the paper size as set in the driver. If you are going to print to file, and send out to a lab, you will need a print driver that lets you set any required paper size. The print to PDF driver is useful here as it lets you set, and save, any custom paper size you want.
Once I have the driver setup complete then I go ahead and set up my printing settings. I normally only print one image on a sheet, so mostly I just the the Single Image/Contact sheet layout option. Having rotate to fit checked in the Image Settings can be useful, but I not normally have zoom to fit, because I will have cropped to the correct ratio. All that I usually have left is to position the image in the Layout section, using margins, grid, and cell size sliders. I don't usually use any of the other options, so I would then be setting the Print Job options. Since you are printing to a local printer you will chose to print to that, rather than to JPEG. Set the resolution to match the printer, and sharpening to taste. I always select the correct printer profile at this point, although when using a proof copy Lr will override the profile selected here. Just make sure that you don't have printer manages profile.
There is one other tool that is available at this point, Print Adjustment. This has two sliders, one for brightness, the other for contrast. If your images are a consistent amount off, maybe because your screen is too bright or dark for example, you can add a consistent adjustment to brighten or darken the image, or adjust the contrast, so that you don't have to "re-edit" all of your images. My monitor matches my prints pretty well anyway, and because I do the proof copy, I have the option to adjust that to produce a well matching print.
At this point I will normally click the + at the top of the Template Browser section of the left hand toolbar, and save the settings as a new template. That will make it much simpler next time, Lr will even take care of changing the printer driver settings for you if necessary. Lr will also have an option for you to "name the print" it is in the small bar that runs across the top of the image window in the Print module. What this does is create a collection in the Prints collection set, and add the currently selected image/s. Once you have the collection all you need to do is add the new images to the collection.
Well that is how I use the Lr print module, hope it is of some use.
Alan
Edit
I forgot to add that using paper matching when using proof colours in the Dev module will help in assessing that change between a transmissive monitor display, and the reflective paper display, for both brightness and contrast. In addition the Histogram changes from it's normal percent brightness to absolute 0-255 values, and is based on the chosen profile, and not Lr's version of ProPhotoRGB.
