To remove slack adjuster you will need snap ring pliers and a regular pair of pliers or vice grip and whatever adjustment tools you need to back off the brakes and probably a hammer.
First chock your wheels
release parking break
get under truck
back off (loosen) the brake
remove cotter pin through the clevis pin
remove the clevis pin
back off brake a little more to get the slack adjuster out of the clevis
remove the snap ring holding the slack adjuster to the S cam
remove the flat washer behind snap ring
slide the slack adjuster off of the S cam
reverse the process to reinstall
Some slack adjusters have two clevis pins a small one and big one and you must remove both. The clevis is that attaches the slack adjuster to the brake chamber rod.