Begin: Base Vectors

Step 1: Normalize vectors by dividing its dimensions to its length

Note: This step is to eliminate length value of vector from the calculation.
Its not applied regularly.

Step 2: Calculation of dot product

Step 3: What it represents?

This value represents perpendicular projection of v1 to v2
or cos angle between these two vectors
if the value is negative, it means projection is on reverse direction.

Step 4: Self experimentation and comprehension

you can test it by giving max min an mid point values.
for instance,
when vectors are perpendicular to each other dot product is 0
when vectors are overlapping dot product is 1
this value will occilate between -1 and +1
if you do not normalize the values, then the value will be cos * length of v1 and length of v2.