1. You can't have a 'elseif' followed by an 'If' because your 'elseif' is already an 'If' statement
2.FormCalc 'if' statement operators are used as letters, so to have 'equal to' is 'eq', to have 'lower than' is 'lt', to have 'greater than' is 'gt', to have 'lower or equal to' is 'le'... etc...
To assign a value to a field or variable you must use the '=' sign
If (Field1 eq "A") then
Field2 = "10"
elseif (Field1 eq "B") then
Field2 = "8"
elseif (Field1 eq "C") then
Field2 = "6"
endif