The addon includes the Blender Addon Updater that allows to update the addon easily from within Blender. You will also be notified if a new version has been released. You can enable/disable that behaviour in the addon preferences.
Add-On hotkey and settings:
By default, enable the tool by using Ctrl+Shift+V (For Vertex). Watch out if you have multiple keyboards to your windows settings, Ctrl+Shift will cycle the active keyboard.
Use the same hotkey to display the pie menu
Change the tool hotkey from the Add-On settings window
Discover the other hotkeys in the add-on settings, and tweak your own preferences
Use the tool:
Select the object or the vertices/edges/faces/curve points you want to move
Enable the tool using the hotkey (Ctrl+Shift+V by default)
With the tool enabled use the same hotkey (Ctrl+Shift+V by default) to open the pie menu and chose what you snap from*to (Vertices and curve points / edge midpoints / face centers)
Finally, to snap you have two options:
Click and drag:
Move the mouse over the point you want to snap FROM
Click an hold the right mouse button, mouve the mouse over the point you want to snap TO
Release the mouse
Two-Clicks:
Click on the point you want to snap FROM
Click on the point you want to snap TO
If you want to cancel the operation:
Press Right Mouse Button or ESC key to cancel the translation
Important notes:
This tool is not made to use on very high poly objects, and performance might get poor when many really heavy objects are under the mouse. Look at the documentation page to find more information about this.
Update the Add-On:
In the Add-on preferences, scroll down, click on "Check now for QuickSnap update"
If the same button now says: "Update now to (x,y,z)" it means that a new version exists. Click that button to update, then restart Blender.
Here is a video showing how ot update the add-on from within blender: (You need to click on the play icon in the top right corner)
Bug Report:
If you have an issue, first check that you have the last version of the addon (Instructions above)