First of all, it is good to know, why you even need companies in Q. You can read it here: Why do I need companies?
You have two options when you want to create a company in Q.:
1. There is the big pink "+" button on the left, where you can quickly add a company
2. Go to the company overview and click on the pink "+" button to create a company
Now there is a Pop-Up where you can add different information. By clicking on the camera icon, you can add your company logo. Furthermore, you can add here the company name and its industry. Then you are done with the basic information.
Now you can decide between save your information and add further contact details.
Here you can add any number of contact details, when you click on "+add Row". You can decide between Phone, Email, Address and URLs.
When you want to add an address, there is a new pop-up, where you can get more in detail. Here you got a selection of type, addressline, zip, city, state and country.
Then you just have to save all the information. Now you can find the company in your company overview.