Short answers, pulled from the story.
Stefan Dušan was crowned Emperor and autocrat of Serbs and Romans on the 16th of April 1346, Easter Sunday, at a great assembly in Skopje. The first Serbian Patriarch Joanikije II performed the coronation ceremony, attended by the Archbishop of Ochrid, the Bulgarian Patriarch Simeon, and religious leaders from Mount Athos.
Dušan's Code is the legal code proclaimed by Stefan Dušan on the 21st of May 1349 in Skopje, containing 155 clauses with a further 66 added at Serres in 1353 or 1354. It is considered the first recorded code of Serbian public law, with heavy emphasis on criminal law drawn from Byzantine tradition. The code remained in force in the Serbian Despotate until the Ottoman annexation in 1459.
Dušan besieged his father Stefan Dečanski at Nerodimlje after Dečanski sent an army into Zeta against his son in early 1331. Dečanski surrendered on the 21st of August 1331 at Petrich and was imprisoned on the advice of Dušan's advisors. Dušan was crowned King of All Serbian and Maritime Lands in the first week of September 1331.
At its peak, Stefan Dušan's empire stretched from the Danube in the north to the Gulf of Corinth in the south, with Skopje as its capital. It encompassed all Byzantine territories in the western Balkans as far as Kavala, including Epirus, Thessaly, Aetolia, and Acarnania, with only the Peloponnesus and Thessaloniki remaining outside his control.
The Ecumenical Patriarch of Constantinople excommunicated Dušan in 1350 because he had elevated the Serbian Archbishopric to a full Patriarchate in 1346 and brought Mount Athos under Serbian jurisdiction, effectively taking those territories out of Constantinople's ecclesiastical authority. Despite the excommunication, Athonite monks continued to address Dušan as Emperor.
Stefan Dušan's remains are located in the Church of Saint Mark in Belgrade. He was originally buried in the Monastery of the Holy Archangels near Prizren, the foundation he had built himself, but his remains were later relocated to Belgrade.