I'm just a few weeks older to you in the cryptoworld - let me answer this till a more senior member gives a more qualified response.

1. Participating in an ICO merely involves transferring some cryptocurrency (mostly Bitcoin/Ethereum) to a specified address. You should be able to do this in Exodus. The ICO folks have a way to keep track of who invested with what amount (to that end, they may make you create a unique ICO account). They give you an amount of ICO cryptocurrency depending on your share of the total amount received by them (some ICOs have a cap on investment, while some are open).

2. Please make sure you do a lot of reading about the project. This site, ICO reviews on Youtube, discussions on Steemit, reddit; are a good starting point. Unfortunately, there is a lot of 'meaningless ranting/currency-bashing', but there are surely gems of advice hidden between them.

3. Bear in mind that altcoins are receiving a lot of new attention and everyone is looking to make a fortune. Please make sure you don't get carried away and invest with whatever you can afford to lose. If you've been following the action in the recent weeks, the price-action in cryptos is very volatile.

Hope you end up supporting some good ideas & end up rich too