If you intend to vote in the Indiana primary elections, you need to get registered to vote if you aren't already. From the Noblesville Ledger article:
If you're going to vote in the May 2 primary, you've got to register by 4:30 p.m. Monday.
The stakes are high. Officeholders will determine tax rates, decide how schools will operate, prosecute criminals, establish budgets for poor relief and township fire protection and run communities and county offices, among other duties.
In northern Hamilton County, 86 names will be on the Republican and school board ballots. A handful of Democrats are challenging some Republicans and those races will be determined in the Nov. 7 general election, but many of the offices will be filled when votes are cast May 2.
What this means is that in many counties across Indiana, often one party is so dominant that the primary election is the de facto election, as the second and third parties are so distant that they fail to post a significant challenge. In some counties, the second party doesn't even post candidates. This is can be the case for Democrats in Hamilton and other counties, and Republicans in Lake and other counties, where the Libertarians will post more candidates in November than the minorty major party.
The Libertarian Party of Indiana currently has minor party status, and does not participate in the primary elections. Libertarians spare the taxpayers the expense, and host their own county conventions.
The law is such that if you vote in the primary election and select either a Republican or Democratic ballot, you are making the statement, under the penalty of perjury, that you intend to vote for that party's candidates as the majority of your votes in the general election. Here are your options if you vote Libertarian and wish to vote on primary election day:
Simply ask for an independent ballot. There may be local issues on the primary ballot, but it is unlikely. Independent voters can still cast votes for candidates for non-partisan office such as school board.
If you intend to cast the majority of your votes for Republicans or Democrats, select that ballot. You can still split your November ballot and vote for Libertarians.