If you do not have a Facebook page for your business, then we highly recommend changing that.
And you can start by logging in.
On the left hand side of your page you will see a column that lists "Favorites" such as your News Feed and Messages, then below that there is a section called "Pages." Here is what it looks like. 
If you hover over the "Pages" title, a blue "MORE" link will pop up. Click on it and it will take you here:
Click on "+ Create a Page" on the top right.
After that, Facebook will ask you to identify what kind of page you want it to be. Click on one of these options:
Next, it will ask you to choose a specific category, type your company name, agree to Facebook's terms of service and click on "Get Started".
You will be brought to the "About" part of your page set up. Here you should enter a description of your company, add your website's URL, and more.
To continue on, click "Save Info." Your next step is to choose your profile picture. The easiest way to do this is to upload from your computer.
All you need to do is click "Upload from Computer", find it and click open.
After that, it will ask if you want to add this page to your favorites and if you want to promote it. You can skip this steps by clicking on "Continue".
Finally, you have created your page!
If you would like to learn how to add an administrator to help you add content to your page, check out this article in our support centre.
LinkedIn
To set up a linkedIn Company Page is much simpler, though just as beneficial.
Start by logging into LinkedIn. From there go to the "Interests" tab at the top navigation bar and choose "Companies."
It will bring you to the companies section. Find a "Add a Company" link on the far right hand side of the screen.
It will ask you to verify that you are a legitimate company by imputing your company email which should be [your name] @ [your company].
Click "continue" and you will find a wide range of information that you can put into the page about your company including: language, company description, company type, size, URL and much more.
Below is a couple of photos that will give you an idea of the set up. There is such a wide array of information that you can input, we can not take you through every box. However, it is very straight forward but here is LinkedIn's Creating a Company Page how-to article in case you have more questions.
On the right hand side of the page, when you have input the information that you wish to start with (the more you enter, the higher the chances of people finding it), click on PUBLISH!
And now it is all ready!