Without being unkind, you have a long way to go before you start up your business.
The most basic things (apart from knowing photography) are copyright and contracts.
Without these you are going to potentially get either into a lot of trouble or do yourself out of business.
Copyright - is automatically yours as the photographer. It can be assigned or sold to someone else but this is NOT recommended.
In the UK being the copyright holder gives you the right to copy, distribute, publish, sell etc your work. There are exceptions and one of them is when you are a portrait and wedding photographer.
As such when clients engage you they are entitled to a certain amount of "privacy" and section 85 of the copyright act (in the UK) kicks in.
This basically is the "Private and domestic" commissions provision which means the customer has the right to NOT have copies issued to the public or displayed.
This is where your contract (terms and conditions) comes in and you should include a paragraph with which they sign away this right and give you the right to use the shots for your own display and advertising purposes.
There are a thousand and one things which you need in your contract such as cancellation terms, payment terms, failure on your part through equipment/illness etc etc etc
You need to engage a solicitor to ensure that whatever you eventually put together will stand up in a court.
If you want examples then you can probably find them on the www but amending someone elses is not as good as having your own drawn up from scratch.
p.s. ignore idiots like Roger Lathbury. He obviously knows nothing whatsoever about copyright if he think the client owns copyright just because they pay you.