Help on create SSL certificate for MUP on AWS EC2

Hi all,

I deployed my meteor with MUP on AWS EC2 ubunto, and it is working now.
I met problem when adding SSL certificate when following the MUP’s instruction on SSL in this link:

When trying to get ssl.pem, it says we can follow this guide: “Check this guide to do that” <link on the “guide”>

I have a few problems here:
(1) my certificate is bought from namecheap.com, and they sent me four crt files:
• Root CA Certificate - AddTrustExternalCARoot.crt
• Intermediate CA Certificate - COMODORSAAddTrustCA.crt
• Intermediate CA Certificate - COMODORSADomainValidationSecureServerCA.crt
• Your PositiveSSL Certificate - www_mydomain_com.crt
. Besides above four files, I have my own private key file.
But according to http://alexnj.com/blog/configuring-a-positivessl-certificate-with-stud.html, I need 3 files instead:
<1> Domain certificate; <2> Intermediate certificates (in our case, the PositiveSSL CA)
<3> Root CA

I am confused which 3 of 4 files from namecheap.com corresponding to the required 3 files…

(2) For the stud command mention “stud /opt/stud/certs-assembly/bundle.pem -u nobody”, should I run it in local? or run it in AWS EC2?
My mac does not have stud, need to install it…

(3) some people mention the private key needs to be decrypted. Can some people confirm this?

Hope to get some help soon on this
Thanks a lot!

Some links mentioned above:

When trying to get ssl.pem, it says we can follow this guide: “Check this guide to do that” <link 2> http://alexnj.com/blog/configuring-a-positivessl-certificate-with-stud.html:

some people mention the private key needs to be decrypted. Can some people confirm this?