How to declare variables, unique id etc... in C#

[Art2010]

Hi,
There is a method (I guess this is a method) DrawArrowUp("tag1", true, 0, Low[0] - TickSize, Color.Red); in C# where "tag1" is user defined unique id used to reference the draw object. I do not know how to declare this id and pass values? I'm not C# programmer. Can anybody help please? Also, would like to know what means Low[0] please?
Full descr. of parameters below:

tag - user defined unique id used to reference the draw object. For example, if you pass in a value of "myTag", each time this tag is used, the same draw object is modified. If unique tags are used each time, a new draw object will be created each time.

autoScale - Determines if the draw object will be included in the y-axis scale

barsAgo- The bar the object will be drawn at. A value of 10 would be 10 bars ago.

y - The y value

color - The draw object color (reference)

Thank you very much.