The .zip doesn’t install in Blender
Please un-zip the archive and install the .py script.
How do I activate an addon?
Use this 20 sec guide – https://youtu.be/wOv4oHO5Kqg
Properties ‣ Object ‣ Transform ‣ Origin Align
Snaps the origin of selected object(s) to the side of the model specified or to the grid. Exactly how it does this is decided by the settings
Side of the mesh to align the origin to. Top, Bottom, etc… it uses the world X, Y, Z to determine what is forward (X, front; Y, right; Z, up)
Centers the object origin on the center of the object’s bounds before snapping. This can be seen as similar to ‘resetting’ the origin point before snapping occurs
Center Enables the smart center feature, measuring the locations of the vertices to find the optimal ‘center’ point. So for example snapping to the Top will get the vertex with the highest Z value and find the average bounds location of all vertices with the same Z value
Rounds the vertex locations to this number of decimal places. Blender appears to struggle at high precision, and usually a precision of 1 decimal place is adequate anyway