The Beginning of World War 1 was very complex. Germany had a very good plan to invade France and Russia. The Central Powers( Austria-Hungary and Germany) looked like they going to win when the Ottoman empire joined.
How it happened
The main reason World War 1 started was the annexation of Bosnia by Austria- Hungary which angered Serbia because they wanted Bosnia. Soon after Galivo Princip, assisted by the Black Hand, a Serbian program to unify the Balkans, shot Archduke Franz Ferdinand and his wife, Sophie. After the assassination, Austria- Hungary sent an ultimatum, Serbia declined and Austria-Hungary declared war on them.
The Schefflhen Plan
The Schefflhen Plan was a German Plan to invade France and Russia at the same time. Germany asked Belgium for military access to invade France, Belgium declined and Germany declared war on them. Soon after in Germany’s shock, Russia had got their army ready and was heading towards East Prussia.
Bulgaria and the Ottomans join the Central Powers
Bulgaria and the Ottoman Empire joined the Central Powers in 1915, a year after the war started in 1914. Soon after, Britain launched a attack on the Dardanelles Strait and failed. In late 1915 an army of Germans, Austro- Hungarians, and Bulgarians invaded and finally took Serbia after three tries.
Next will see what happens in the middle of the war, but for now see you next time!