Poland has a civil law legal system. Although decisions of the Supreme Court are usually followed, there is no binding precedent as we know it in common law jurisdictions.
In order to come into force, statutes have to be published.
A statute is universally binding law in Poland. The right of legislative initiative belongs to the Deputies of the Sejm (think Represenatives of the U.S. House of Representatives), at least 15 members of the Senate, the President, or the Council of Ministers. The Constitution also allows for popular initiative if a bill can gather the signature of 100,000 citizens.
A detailed description of the legislative process is available in English on this site.
You find on the bill tracking site that other groups can draft legislation, write reports, and take in opinions even before the legislation reaches the Sejm. The Government Legislation Center (RCL) gathers information on that process as part of its role coordinating the legislative process.
The highest court in Poland is the Supreme Court. Below the Supreme Court, there are “common courts," which also function as appellate tribunals from the lower district courts. The Polish system also has administrative or special courts for family, labor and social insurance and a separate body for economic arbitration.
President can ask the Constitutional Court to weigh in on the constitutionality of legislation before she signs it. The President can also make an follow-up application to examine an act or international agreement at any time. Making the application does not affect the applicability of the act. The Constitutional Tribunal can cancel a legal act because it is against the Constitution.
Subject law collections provide access cases and legislation from Poland and other countries pertaining to a specific subject area. Using a subject law collection is particularly helpful when you are comparing the laws of more than one country.
For more suggestions on subject-specific collections of laws, please see GlobaLex's Foreign Law - Subject Law Collections on the Web research guide.
European Union law is an additional source of law in Poland. To be in force in Poland, EU law must be interpreted into Polish and published in the Polish version of the Official Journal of the European Union.
European Information and Documentation Center (OIDE) supports the Sejm by providing information about EU law and trying to liaise between Poland and the EU. On their website, you can find information about the Sejm's relationship with the EU. It also has a database, the UST Database which contains implementation of EU law in Polish legislation. I think you're better off bringing up all of the documents rather than trying to search. Usually, a database from a foreign country is searchable in that country's language.
This will let you see Polish legislation that implemented EU law.