How do we assign alpha/beta status in polysaccharides?
Here is an explanation for alpha- and beta- glucose.
What it doesn't say is that the alpha-glucose can convert to beta-glucose and back again. Once the linkage is formed, it cannot change from alpha to beta.

Alpha linkage has the oxygen (on the aldehyde or ketone) below the ring and the beta has it above the ring.

Down the page, it shows beta-Maltose. The label beta (for the right most oxygen) is unimportant since the link has to be alpha for it to be maltose. A beta link would result in a molecule of cellobiose.