jojo - I'm gonna offer some basic suggestions.
Don't be discouraged, Don't feel overwhelmed! But you DO have some important homework you need to do in order to help you and your travel party have a great trip.
The good news is that 1) You can do it, you just need to jump in and start; and 2) Everything to need to figure out, all the little tricks and tips, it's all available right here on this website, for free, and easy to find -- and for anything else you need help with, people here will gladly answer questions and set you on a path for success. The answer to every question you might have has already been answered here hundreds of times before, and there are lots of simple, step-by-step resources to help you with the process. You just are going to need to read a bit, watch some videos, do some planning.
You do have some challenges: Your trip is coming up quickly, so you need to get cracking on planning (many experienced travelers plan long in advance but your trip is very soon); you have a long list of places you want to see but limited time (that's true for everyone), you just need to prioritize and develop a reasonable plan. Don't panic, everyone goes through all this to some degree for every trip.
Here are some good starting points, as you follow the links, you will discover a vast repository of useful travel knowledge that others have left for you; you can apply all this accumulated knowledge and experience to give yourself a better trip.
Start with the classic Rick Steves "Travel Skills" videos. This 3-part series consists of short videos discussing and demonstrating the basics of "doing Europe" - How to get around, train tickets, rental cars, flights, money, shopping, avoiding pickpockets and other scams - almost everything! (these were originally on TV, now you can watch with just a few clicks). These videos are short (about 25 minutes each), fun and inspiring - they will get you motivated, watch them!
Here's where to find them...
On this web page, look at the navigation menu near the upper left corner of the browser window (scroll up to the top of the browser page), under the big, blue "Rick Steves Europe" logo...
Click Watch, Read, Listen
Under "Watch Read Listen", click Watch the TV Show
In the center section, under "Watch Full Episodes of Rick Steves' Europe", scroll down towards the bottom on the list, and click on Travel Skills to expand that list.
Under "Travel Skills", note the three shows on travel skills: European Travel Skills I (2012), European Travel Skills II (2012) and European Travel Skills III (2012) . That's your first homework assignment.
Click on the first of the 3 episodes, European Travel Skills I (2012). Sit back and watch it. Then watch the 2nd and 3rd episodes in the same series. You will learn many things, it will be fun, you will feel empowered, each skill will help you have a better trip.
There LOTS of other videos in the series that can help you plan and prepare for your trip - explore them!
Here are other sections of archived material you should check out - the sections on Travel Tips and Travel Planning, especially the sub-section on Trip Planning.
You can do it! Good luck and have fun!