The Golden Pass train is a special tourist train which runs Luzern - Interlaken - Spiez - Zweisimmen - Montreux. There are also hourly regular trains on this route, as there are on all Swiss rail routes. It is not one through train, you have to change at Interlaken Ost and Zweisimmen, and usually also at Spiez.
The nearest point on the route to Lauterbrunnen is Interlaken, you could pick up the train there.
But, this begs the question, how are you getting to Lauterbrunnen? The usual way is by train, and the only route to Lauterbrunnen is via Interlaken. So you just double back the way you got to Lauterbrunnen. And, if you came by train via Interlaken, you will already have traversed at least a part of the Golden Pass route.
I suggest you look at the Swiss rail map here, and familiarise yourself with where these places are: https://www.swisspasses.com/railpass/overviewmap_en.pdf
You can look up times and prices for all train in Switzerland on the Swiss Federal Railways site: www.sbb.ch/en