I'm going through the tutorials and I have a question about how something works.

In the A05 file from C:\XYZ\pd\doc\3.audio.examples:

Can someone explain to me how the [pack 0 50] "makes a ramp to avoid clicks or zipper noise"?

[pack 0 50] doesn't do anything but pass a message to [line~]. Read the help file for [line~], the first integer in the message is the 'destination' and the second the time. So [line~] will proceed to whatever number is on the left input of [pack], in this case the rms amplitude, in 50ms.

ahh thanks! I get it now.

I want to ask that how I can initilize an array and store values in it.

check out the docs;
2.control.examples/15.array.pd
and
2.control.examples/16.more.arrays.pd

for a good start to initializing and writing directly, or writing with trig functions. To write audio or data there's the objects [tabwrite~] and [tabwrite] respectively.

How can I store the values in an array and how can I add the values that are stored in an array??.