In most cantons, voters elect representatives to the National Council by proportional representation. This means that the mandates are first divided between the lists according to the number of votes obtained, and then allocated to the people with the highest number of votes on the list.
In the cantons of Obwalden and Nidwalden, voters elect representatives to the National Council using the simple majority system. This means that the candidate with the highest number of votes is elected. If only one valid candidate is submitted within the deadline (by noon on 4 September 2023), that candidate is tacitly elected without a popular vote.
ch.ch gives you an overview of the candidates.
To find out how many representatives represent your canton in the National Council, have a look at the page Number of seats in Parliament.
ch.ch provides detailed information about the Swiss Parliament.
ch.ch explains How the Council of States is elected.
ch.ch. has a page on Voting material.
If you are planning to travel during the election period, have a look at the page Not at home but still able to vote.
ch.ch provides the lowdown on Transparency of political funding in Switzerland.