Both lounges open at 1 PM (as of 9/2/18), TSA at Terminal B is not open until 12:30 at the earliest.

SAS Lounge: After Security Gate/Area: B60

Lufthansa Lounge: After Security Gate/Area: B68

Both are located at satellite B3:

Going to LH or SAS lounge from various points:
From Terminal B International arrivals: walk to B3 security;
From Terminal B's United Gates: walk out of B1 security and enter B3 security;
From Terminal A: United airside shuttle or outside AirTrain train to Terminal B;
From Terminal C: United airside shuttle or outside AirTrain train to Terminal B;
(Note: there are two shuttles; only taking the shuttle to Terminal B and ask the driver to drop off at B3's LH lounge entry; not the United gates at B1).

Return to Terminal A or C: Airtrain train only.

The following was copied from west_end_NYC post.

I made my first visit trip to the EWR Termimal B Senators lounge last Friday as I had an extra hour to burn (notes: calculate your total journey time from different entry points; too risky with short layover time at EWR) before an 8:35PM flight out of Terminal C. I found the process of acccessing the lounge and getting over to Terminal C quite seamless:

- TSA at Terminal B scanned my UA paper boarding pass and reviewed my ID - no questions asked and was immediately let through.

- Note there is no TSA Pre-Check at Terminal B for the international gates so had to remove shoes, etc, and clear through the full body scanner. There was only a short line so only took ~10 minutes to clear through security.

- Proceeded to the LH lounge and showed my MP Gold card and UA BP at the check-in desk and again, no questions asked, and was invited to head into the Senators lounge to the left of the desk.

- Nice food spread including two entree choices, sandwich choices, and self-serve wine, beer and liquor with several varieties. Not quite the quality of the new Amex Centurion lounges I have visited but far better than anything available at the EWR UC, particularly noting it was all complimentary.

- The journey over to Terminal C was much easier than I anticpated and considerably faster than the 1 hour transit time referenced in earlier posts. I took the Airtrain one stop to Terminal C. Door-to-door from the LH lounge to the UC right past security took just 15 minutes (the C-3 Pre-Check line was not very long).

Notes: allow plenty of time for your return journey because time for passing security at Terminals A and C varies greatly, depending upon the time of day. Terminal A does not have a full PreCheck.