How to use the flex tool?

Here's the Tutorial.

Answered with a tutorial: https://grabcad.com/tutorials/how-to-use-the-flex-tool

I went ahead and use dit... how it works is very easy to explain with a long model. Try an i-beam.
Go to Insert>Features>Flex...
Select your i-beam (or whatever it is)
Now take a gander at the 4 options just below the blue object selection box. The options are: Bending, Twisting, Tapering and Stretching.
You may also have noticed a red and green plane at the start and end of your model.
When Bending: fill in a degree of bending, and you will see that the model inbetween the red and green planes will bend uniformly.
Twisting lets you twist your i-beam (or whatever) as if the green plane is held ina clamp end the red plane in a wrench, which is then turned as far as you wish it to go. (Fill in an angle).
Tapering will deform your i-beam as if the red plane side is scaled up, the green plane side is scaled down, and everything in between follows that as if its made form rubber band. (It can also be tapered the other way around)
Stretching will do just that: stretch your model uniformly.

SO far, you may have found out yourself. When it comes to lofts, I expect the flex tool to behave similar. If there is any specific thing you dont get with the flex tool, please update your question to accomodate that... ;)

GOOD TUTORIAL as usual..