How did they attach the Tachash-skin cover to the pole?
What is the significance of the pole?
Ibn Ezra: The pole was used to suspend the Tachash-skin cover with the Menorah and its administering vessels and to carry it when they traveled, since, unlike the other holy vessels, the Menorah did not have staves with which to transport it.
Hadar Zekenim: The Menorah was carried on top of the pole. It did not hang from it, lest it drag on the ground, for it was 18 Tefachim tall. 1
An average person this tall, until his head or his shoulder (Tosfos Bava Basra 100b brings both opinions). Either way, it is prone to drag. (PF)