His intention was not to conquer Ukraine. Why would Russia want more enemies bordering land it controls.
One intention was to ensure that NATO missiles weren't planted on the Ukraine/Russia border which would have been within a few minutes from Moscow. Once launched at Moscow, and not knowing the type of warheads used, Russia would have to make the decision to reply with nukes just in case, which is not a decision any leader would want to make.
A second intention was to protect the Russian speakers in eastern Ukraine from persecution by the Kiev regime, which was rapidly ramping up.
He also needed to protect the mostly Russian speakers in Crimea (who by a huge margin voted to join Russia) plus the only Russian warm water military base located there.
If Ukraine had agreed to remain neutral, without NATO missiles within it's borders, all the death and destruction could have been avoided.
