Simple quick reference of putting install lightroom preset, lightroom preset extension is “.lrtemplate”

Free Preset:

27 Free Lightroom Presets By Bryan Wheeler 
Link here

Basically, you can put your presets inside:

Mac
~/Library/Application Support/Adobe/Lightroom/Develop Presets/
Where “~” is your user directory.

OR

PC
C:\Documents and Settings\<your_username>\Application Data\Adobe\Lightroom\Develop Presets

If you can’t find it, you can follow below:

1. Open Lightroom.

lightroom_preset1sm

2. Go to Edit –> Preferences

3. Under Preference go to Presets tag and chose Show Lightroom Presets Folder
lightroom_preset3sm

4.Open the folder and go inside Lightroom –> Develop Presets
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5. Create a new folder. eg. I call it “free_preset” and put the Lightroom presets “.lrtemplate” file inside and you are done! Now close the lightroom and reopen it and you should able to see and use the new presets that you have installed.
lightroom_preset6sm