Can someone quickly go over the procedure in voting in a Presidential primrary.....

It varies by state.

 

Some states have an open primary where people from any party can vote to nominate a candidate for a specific party. In some Primaries, only party members can vote but Primaries are subject to similar policies as elections - although they can vary by state. In Primary elections, other issues of binding means can be determined - and states usually only offer one date for Primary voting.

 

Some states have caucuses. These generally have lower turnout than primaries because only rank and file party members can participate (although being considered a party member is sometimes as simple as showing up). In a caucus you can be cajoled into swinging your vote by other party members, paraphenalia is often in the room, and it can be held in a town meeting style where supporters literally gather in a corner and are counted, like in Iowa, or like a traditional voting system - although you can talk and be pressured. These are generally more informal. Michigan has a voting style caucus but still will only attract 100,000 voters, in a state with over 15 million people.