Depending on how your System prefs are set, F3 will do a variety of window-juggling tasks…
If Prefs > Keyboard > Keyboard is set to default, with "Use all F1, F2…" unchecked then they will work as stated, if it's checked you will need to add the Fn key to each of these commands.
F3 will toggle Mission Control - all windows of all apps & Desktops spread out so you can see them.
Cmd ⌘ F3 will toggle desktop view only.
Ctrl ⌃ F3 will show all windows of only the frontmost app *[this is likely to be the closest to what you need.]
Shift ⇧ F3 will do the same as just F3 … only really really slowly [for presentations etc]
Opt ⌥ F3 will bring up Mission Control prefs, where you can tweak other behaviour.
You can also go directly to a given tab by right-clicking the app icon in the Dock, though it only shows the frontmost tab's title for each window.