How to use the groups as a filter for a bar chart for category vs sales?

Let's say we have a bar chart for category versus sales like below-

Now let's create a group on the category by selecting two of these categories-

Now just right click on the created group and select show as a filter. you will find a filter now being shown to the user with only two options, one with the category and another with the categories you have added in the group.

I have a date related hierarchy that has some specific date format. Is there any option to change the date format in the hierarchy?

You can change the format of the date in the hierarchy by selecting the format option in the date. from the formatting pane, you can select the Reserve format or you can provide your own custom format as well.

If you want the URL to be open in another tab you can use target=_blank. This was the same way HTML tag works. below are common tags you can use in the URL parameter in dashboard action-

linktarget=_self, opens links in the same tab/window

linktarget=_blank, opens links in a new tab/window

linktarget=_parent, opens links in parent window (for embedded views)