How do I prepare for current affairs for the CDS and SSB?

Start developing the habit of reading newspaper (any newspapers like THE HINDU or INDIAN EXPRESS ) or current affairs magazines (like vision IAS , Yojana etc).

There are various YouTube channels( like Shaurya aur Vivek defence academy, world affairs, study IQ etc) you can follow to have a good hold on your general awareness. It's very important to have a perspective and an opinion of your own in your SSB.

You can also follow various websites like ORF , CHANAKYA FORUM , WION also as they publish good articles relating to important national and international affairs.