Functions Library is a .dll which means, it can be referenced easily. To use it you simply just make a reference to your project and type in the usings "using Functions;" and your good to go.
In the namespace Functions are 2 more namespaces which are "Math" and "IO".
.Math includes functions for calculations for or with Pi, Power, Squarer root and more. While IO includes Creating a TextFile, Deleting it, reading it and writing to it.
Just to name those few, there are more functions...