In most startups, the founders will typically appoint themselves to the board initially. From there, others will get added to the board as the company grows. Typically, the first outside individuals to be on a board are either important advisors or your first institutional investors (often in your Seed round). Not all investors will be added to your board, and the decision often comes down to their investment size and how valuable they are to your venture. When you are ready, talk to your lawyer about everything that is needed to set up a board, which typically involves the Board member signing a Board Member Agreement. Boards often handle big corporate matters like allocating stock, authorizing fundraising, taking large loans, or other big decisions that can materially affect the financial performance of the company. Boards are typically updated bi-weekly or monthly, with quarterly, bi-annually, or annual in-person board meetings. Remember, as more people are added to your board, the founders relative voting power is decreased.