WW1 brief summary of my knowledge i know im dyslexic

What is your question?

That is, essentially, the US High School standard explanation of the war. It isn't technically wrong, but it is highly simplified and entirely from the perspective of the US's involvement in the war.

The perceived immorality of unrestricted U-boat warfare was the bigger straw on the US-camel's back.

Austria blamed this on serbia

Sort of, not really. Those ruling Austria-Hungary saw their opportunity to, in their words, 'eliminate Serbia' and took it, with the assassination as their justification. They didn't really think Serbia had actually arranged it, but they deliberately engineered a war because they thought they could get away with it.

This caused germany to get involved and back up austria.

You have this backwards. Austria-Hungary went to Germany and asked for support if they waged an aggressive war on Serbia. Germany (really, just the kaiser) agreed because the Austro-Hungarian diplomat, Szogyeny, knew the kaiser very well, had been in Berlin a long time, and knew how to talk to him.

Germany then escalated this and declared war on austria and france and russia as france were allies with russia.

Germany did not declare war on Austria-Hungary.

Germanys plan to defeat france was to march through belgium but belgium troops stood up to the germans and the Germans invaded them anyway.

It is arguable to what extent the Schlieffen plan was even a thing, and it's debatable to what extent it could ever have succeeded, especially in the face of stiff Belgian resistance:

It is therefore clear that at no time, under either Schlieffen or the younger Moltke, did the German army plan to swing the right wing to the west of Paris. The German left wing was never weak; rather it was always very strong – indeed, the left wing, not the right, might well conduct the decisive battle. The war in the west would begin with a French, not a German attack. The first campaign would end with the elimination of the French fortress line, not the total annihilation of the French army. It would involve several great conventional battles, not one battle of encirclement. If the Germans did win a decisive victory, it would be the result of a counter-offensive in Lorraine or Belgium, not through an invasion of France. There was no intent to destroy the French army in one immense Cannae-battle. There never was a ‘Schlieffen plan’.

From Zuber, The Schlieffen Plan Reconsidered, War in History.

The uk also had treatys to protect russia and france but belgium was what got them in.

The UK had no actual military alliance with France until after the war began.

Before the message even reached mexico the British decrypted it and told the Americans naturally the Americans were very angry and this is what caused the Americans to join ww1.

The Americans had been supplying materiel and finance to the Entente, and the Germans essentially considered them hostile. The sinking of American shipping by German unrestricted submarine warfare was a major issue for the Americans, and the Zimmerman telegram was the step too far.