Upvote:2
Since you have the private company organizing your trip, they usually would have the answers for you. So please check with them first.
Being an Indian national you need a Schengen visa for your trip; your H1B status will help you to qualify, but does not relieve you from this obligation. The visa rules dictate that you must apply in the country you'd spend most of the time; if you spend equal time, in the country you visit first. Thus you need to ask your organizer for an itinerary to find this out.
You also need to ask if the trip organizer prepares your visa paperwork for you (so you just need to apply/visit for biometrics), or you should apply yourself. In latter case please see many questions on this site about Schengen visa, this topic has been extensively covered. The health insurance is required to get a Schengen visa, and again your organizer should help - but if not, it is easy to purchase yourself.
Keep in mind you might need to arrange other travel to apply for visa - for example, if you live in San Francisco Bay Area, some European countries have only honorary consulates here, and those do not issue visas; the nearest real consulate then is usually in Los Angeles.
Finally, if you just want to read more about the countries, you can research by yourself, using free online resources such as Wikitravel, or Lonely Planet books in your local library. Then if you have more specific questions, such as "is Milano Centrale train station area dangerous at night?", feel free to ask them.
Please also use the search function on this site - Schengen visa is probably the most covered topic here, and it is very likely your question has been asked and answered before.