It would be rare for a first year undergraduate who is not studying law to obtain a work experience position, but you might obtain such a position in your second or more likely in your third year.
You can obtain information about vacation schemes and so forth from sites such as Legal Cheek, and perhaps also Roll On Friday (a site that exists mainly for trainee and junior solicitors to bewail their bad decision in signing the Faustian Bargain and joining a large law firm). Also check out The Law Society, Bar Council, and Inns of Court websites.
If you obtain a training contract, you might obtain funding for legal education, and you might not. That depends on the firm which offers you the contract. The same is true if you obtain a pupillage.
Have you already considered and decided against trying for the Bar?
As you may already know, competition for training contracts and for pupillages is intense. Most of those who set out to become lawyers fail to become lawyers. The attrition rate is high. This is not a reason not to try to become a lawyer, but you need to go into the process with your eyes open, and to have a Plan B.
How much do you know about what lawyers do? Have you any views on what type of law you might like to practise?
I hope that you will enjoy university. Good luck!