Sample size calculation for accelerated life testing

[#1]

I am trying to use the interval explorer for parametric reliability life test planning tool for sample size required for an ALT test but need some clarification on the following questions.         

1. Is the Weibull alpha the characteristic life at stress or at use life? 

2. Is the Quantile the pFail at stress or use life and how does the quantile impact the required sample size?

3. Is the calculated sample size the required sample size per stress or total?

Thank you.