Last year was my first live draft on ESPN. It's relatively easy.
We'll set a draft date and time where everyone should participate. If someone is not able to participate in the draft live, they can go into the site anytime before the draft and pre-rank the players. There is a default ranking, but if you want to change the default rankings, you can (I.e. go in and rank David Wright higher than A-Rod, etc.).
On draft night, you need to go to the league homepage. From there, I believe there will be a link like "Go To Draft" or something like that (I honestly can't remember).
About a half hour before draft time, the draft order is chosen at random by the site.
When the draft starts, the first team (team 1) is on the clock. Each team has 90 seconds to make their draft. If they don't make a choice in 90 seconds, someone will be drafted automatically based upon ranked players and team needs. It then automatically goes to team 2, and so on until it gets to team 10. When team 10 makes their pick, the order reverses and team 10 goes again, then team 9 and so on. It's called a Snake Draft.
That process keeps going until every team has filled it's roster.
When it comes to who to pick and strategies, I suggest picking up one of the Fantasy Baseball draft guides or look online for one. I'm sure the ESPN Fantasy Baseball main page has some resources.