I downloaded the ACM Sigcomm 2015 template but its not compiling and giving me hundreds of errors. Kindly help me. Here is the template link: http://conferences.sigcomm.org/sigcomm/2015/doc/sig-alternate-10pt.cls
The reason is that this template is a CLASS file *.cls so you need to add it in your *.tex document as:
where sig-alternate is the required *.cls file that needs to be in the working directory of your project. You can create this class file sig-alternate.cls by copying the code from the link: http://conferences.sigcomm.org/sigcomm/2015/doc/sig-alternate-10pt.cls and pasting it in any text editor and saving it as *.cls. I hope you got my point.