Sorry, I'm not a huge fan of watching YouTube videos. Regarding the seizures of forts/arsenals, it is important to provide context. For example, the statement "Georgia seizes Fort Pulaski," while true, tells us very little.
Consider:
A dispatch from Charleston states that returns from Georgia indicate that the State has gone largely for secession.
Forts Pulaski and Jackson have positively been occupied by the Georgia State troops, under the Governor's instructions, and it is said that but for this the fortresses would have been taken by an uprising of the people.
Senator Toombs received a dispatch on 3d from Governor Brown, of Georgia, stating that he had ordered the Georgia troops to occupy Fort Pulaski, to prevent the Federal troops from taking it until the meeting of their Convention. Neither Fort Jackson nor the arsenal had been taken, and the Governor gave no intimation that he intended to take them. The Governor issued the order to occupy Fort Pulaski for the reason that he had learned that the Administration had given orders to reinforce all the forts in the South. Other forts have undoubtedly been taken for the same reason. The President, it is understood, did issue such an order, but it was afterward revoked. The President also received a dispatch announcing the occupation of Fort Pulaski by the Georgia troops.
Another example listed is "Alabama seizes U.S. arsenal at Mount Vernon." Again, let's look at the
context:
In an unusual move, Governor Moore wrote to President James Buchanan on the same day to inform him of his reasons for ordering the seizure (Abraham Lincoln had not yet taken office). Telling Buchanan that he had ordered the taking of the arsenal, Moore explained that he had received intelligence that U.S. forces were preparing to reinforce the arsenal and other forts in Alabama and willing to shed the blood of Alabama citizens in order to do it:
…The purpose with which my order was given and has been executed was to avoid and not to provoke hostilities between the State and Federal Government. There is no object, save the honor and independence of my State, which is by me so ardently desired as the preservation of amicable relations between this State and the Government of the United States. That the secession of the State, made necessary by the conduct of others, may be peaceful is my prayer as well as the prayer of every patriotic man in the State.