If, after a general election, no party can get the support of the majority of the members of the Dáil, 2 or more parties may agree to work together as a coalition government.
The coalition parties will agree on who will be nominated as Taoiseach. Usually, it is the leader of the larger party. In recent years, the practice has been to nominate the leader of the smaller party as Tánaiste.
The ministerial portfolios will then be shared between the parties. Usually the larger party will be given a greater number of portfolios. The leader of each party will decide which elected members of the party to allocate those portfolios to.
The coalition government will remain in power for as long as it keeps the support of the majority of the Dáil. If the coalition parties find that for some reason they cannot agree and can no longer work together, the Taoiseach may advise the President to dissolve the Dáil.