Swiss Pass

If you have purchased your pass in the US, you will have to specify the dates of validity, and so it is ready to go. All you have to do is board your vehicle. If asked by a conductor for a ticket, you show your pass. Note that technically, you can be asked to show your passport (to prove it's your Travel Pass and not someone else's); on my recent September 2017 trip this never happened to me, but someone else posted that it happened to them.

If you are taking something that is not fully covered by the Swiss Travel Pass, you have to buy the proper ticket BEFORE you board. But the train from Zurich airport to Luzern is fully covered, so no worries.

If you have any questions or points of confusion, there is a Swiss Rail office right in the airport train station. You could also wait and buy your pass there, if you prefer (that's what I did).

Thank you. Didn't save you any money to buy your pass over there?

Thank you. Didn't save you any money to buy your pass over there?

The price there is the same as posted on the internet. The conductors ask to see my passport as ID when I was there last summer.
The site you buy it at describes what it covers and how to use
https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-travel-pass.html

Where and how do I use the Swiss pass for the first time?

You don't have to do anything, that is the advantage of the pass. Just get on a train, bus or boat and when asked to show your ticket, show the pass.

The prices of the Swiss Passes are fixed, like most Swiss ticket prices. The same price for the whole year until the annual timetable change in December (but they don't change every year).
If you buy from a reseller who quotes a price in a foreign currency (e.g. US $), the price might vary due to the exchange rate, or due to a markup.
You can buy the passes at Zürich airport station for the set price, so there is no financial advantage to buying before you leave home.

Swiss Travel Pass 3 days 2nd class CHF 225, 1st class CHF 358
Swiss Travel Pass 4 days 2nd class CHF 270, 1st class CHF 429
Swiss Travel Pass 8 days 2nd class CHF 398, 1st class CHF 631
Swiss Travel Pass 15 days 2nd class CHF 485, 1st class CHF 765

Swiss Travel Pass Flex 3 days in 1 month 2nd class CHF 259, 1st class CHF 412
Swiss Travel Pass Flex 4 days in 1 month 2nd class CHF 310, 1st class CHF 493
Swiss Travel Pass Flex 8 days in 1 month 2nd class CHF 445, 1st class CHF 706
Swiss Travel Pass Flex 15 days in 1 month 2nd class CHF 532, 1st class CHF 840

The prices are listed here: https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-travel-pass.html

I would add that it makes more sense to purchase the pass at Zurich airport upon arrival. What if your plans change or your flight is significantly delayed? If you purchase it ahead of time in the US, it will cost slightly more and cancellation charges apply.

Also, we will be heading back to Wengen in August after a week there last year (and 2015 in Murren). After you read up on what you want to do, you may want to consider the Berner Oberland pass along with the Half Fare card. Personally, we prefer the BOP when we stay in Wengen as it covers more lifts at 100% from Wengen than the Swiss Pass does. Suggest you read up on the various options and make the decision that is best for you.

The pass will have your name pre-printed on it, but you need to enter your passport number, and sign the pass.

And if it is a FlexPass, you must enter the date of travel in the first box before boarding the train.