Firstly, you need to get Biz Channel Standard version for the file upload. The Lite version seems not supporting file upload feature.
Don't download the file separately from Pay EPF/SOCSO/LHDN. Go straight to download the bank output file that is a zip file contains all the files.
The Userguide is available here: http://www.cimb-bizchannel.com.my/index.php?ch=faq&tpt=&cat=1:15
One Extra Note:
If you're using CIMB Biz Channel for the FIRST TIME, they somehow have a weird setting in the EPF file called "Test Mode". If you have error when on submitting EPF file, what you can do is open the EPF file on notepad, and edit the last character to 'Y' instead of 'N'. then see if it works to unlock the test mode.
don't ask me why they do it on the EPF file >__<
how to setup Kakitangan.com so you can automate the max for your payroll and people operation /onboarding-your-company-to-kakitangan-com-for-the-first-time/