I manage 4 "like" pages for the company I work for. It is very easy to do.
Here is the FB help page to walk you through it.
http://www.facebook.com/help?page=255100294550008
They are totally different sites. I log in using my regular FB account and then I can go to pages and I am that person automatically. I do not log in differently. You can choose to switch to your own name or the business name on the page too. But it is a totally different but linked account.
The only people who see what you post on your business are the people who have gone there and "liked" it. If your friends have not liked it they will not see your posts and vice versa. No one on that business page will have access to any other account page.
The only ones that can make changes to the account are the ones you allow to be administrators.
I took a class at the local Vo-tech called FB for your business. About the first hour was wasted, the teacher was having to walk people through making their first ever email account so they could get an email address to make a FB account...yes, their very first email account.
It was frustrating for those of us that are FB savvy. I recommend you find the local high school vo-tech and call them to ask if they offer any adult training classes. This is one they do every semester or so.
She taught us one very important thing. You need to always make sure you have at least one other administrator. If you every get booted off the account you loose the business page and are taken off as admin. You cannot every get that back by searching or any other way than to be invited by another admin. Therefore you need to make sure you always have a relative or friend that you can make an admin for the page. They have the same authority as you though. They can post stuff and change settings too.
I have an alter email account so I made a FB page with it and it's my other admin on my own personal "like" page for my own business stuff. But for the 4 that I manage for the company I work for the owner (hubby), their daughter, and their son are all admins. The daughter will occasionally come in the store and say she likes something I posted or some thing didn't quite look right. She is always kind and nice so I really don't mind.
If you have a smart phone you'll need to add the FB app. Once you get logged in and stuff you can see the little lines on the top left. Click on them and it will show you a menu. Scroll down and you should see your page. Touch it and your business page should show. You may need to click on the bottom where it says "wall" instead of "activity".
To add a picture from your phone to your page and not your personal page you'll need to be on your "like" page. Under the world it will say Share a Photo. Click that. An upload option window will pop up. I always click photo.
Then it will ask if you want to choose from gallery or capture a photo. I use the gallery option because I take lots of pictures of girls ball gowns and leos, dance shoes, dance and gym bags, etc.....choosing from the gallery takes me to my phone's photo albums. Choose the one that has the picture you want to upload. Select the photo by clicking on it. You should go right back to the "like" page and the picture should be showing on the post, just add a comment and then click post in the top right corner.
Repeat as many times as you have pictures.
I enjoy this new option for me. I am computer illiterate so for me to know how to do this is so fun!
Good luck. I hope you still take that class though. I really learned so much.