can someone help me on understanding how to use this filter?
Tried 50 different commands but none workx
Welcome, @m2405398
We have some tutorials with examples you can try. These show how to associated annotations in your VCF to common filter terms.
GTN Tutorials for SnpSift Filter: Filter variants using arbitrary expressions
Please give that a try. 
Then, if you are stuck with a particular query, you can share your history with the VCF and explain what you are trying to do. Please leave the failed queries in the history, and we can try to help to get things working.
How to share your history is in the banner of this forum, also here. → How to get faster help with your question. You can post the share link back here in a reply, and note which dataset numbers are involved, then unshare once we are done.
Hope this helps!