Complex sentence: The squadron was formed as part of an initiative by other Entente Powers to keep Russia in World War One by protecting the large stockpiles of Allied material that had begun stockpiling at the ice-free port at Murmansk.
Split into simpler sentences: The squadron was formed as part of an initiative by other Entente Powers to keep Russia in World War One. One goal was to protect the large stockpiles of Allied material that had begun stockpiling at the ice-free port at Murmansk.