How to estimate alpha and beta for beta-distribution in to run pglm regression

Question

I am trying to run a fixed-effects regression model on panel data in R. My dependent variable (the share of workers on long-term contracts) is bounded from 0 to 1, and I use the pglm package. The settings are: effect = "individual", model = "within", family = beta. I get an error: argument "a" is missing, with no default. Apparently, I need to specify the alpha and beta for beta distribution. How could I get them?