I have the following basis, (fllngpwr}, and expression, {exp3}:

fllngpwr={1,\[Alpha]^UnderBar[1], \[Alpha]^UnderBar[2],\[Alpha]^UnderBar[3]}

exp3 = 3 - \[Alpha]^UnderBar[1] + 2\[Alpha]^UnderBar[2] + 5\[Alpha]^UnderBar[3]

I would like to extract the coordinates of the expression {exp3} in terms of the basis {fllngpwr} using:

cordvect =ResourceFunction[CoordinateVector[{exp3},basis,{\[Alpha]}]]

I must have something wrong since it seems to evaluate, by that I mean it fills in the exp3, basis and alpha. For example:

ResourceFunction[CoordinateVector[expression,basis, alpha]]

Any suggestions would be welcomed.

Thanks.