on init B : ZFWCG, ZFW, FOB, W/C, T/D, Taxi fuel, extra fuel, contingency fuel,. All the data is send to the FM part of the FMGS trough MCDU to calculate envelope protection (VLS etc)
On perf page you insert V1, Vr V2, flex temp, conf and ths setting as calculated with dispach charts of the particular airport acording with the load sheet and atis info.
cheers