Installation of plugin into Eclispse Mar.2 (4.5.2) beind corporate proxy

[30atm]

Hi,
My current employer and team uses Eclipse Mars.2 (Release 4.5.2). I cannot use Neon. Which version of CCW-IDE plugin should I use for Mars release?

I do not have access to download from eclipse market place website due to corporate proxy/firewall rules.
I have to download the release zip from github and install manually.

The README.md file in the downloaded zip does not have instructions for offline installation.

Can you please help with those instructions.

regards