I think that is a Shimano free hub. If you are having trouble disassembling it, then take it to a bike shop and let them deal with it. Definitely see if they'll let you watch and explain what they are doing. Don't think of it as paying someone to fix what you wanted to DIY. Think of it as your tuition for learning how to work on your bike. Much better than the tuition you pay by destroying a component doing things you think might get it apart.
Two of the bike shops near me have their mechanics out in front of everyone. One has a lunch bar & grill you can sit at to eat and drink while you watch.