I am trying to provide role based access to folders in Plone 5. I have created two custom groups with member role . I want to provide access to particular user group to view particular folders . Help me with this task.
No idea what you are exactly asking for but using "Sharing" from the toolbar is the way to go for granting local rights to users and groups.
The UI is confusing because of the names it uses.
Think of groups as roles. You have created the two groups/roles. Next to assign permissions or rights to those users on a location basis you use the sharing tab on the particular folders. You would also first have to ensure the folders and the contents are "private" or another state thats not visible to who you don't want it visible to. Then you modify that visibility to elevating those "view" right to those particular groups.