To combine 2 or more variables you can do as the following:
Let A="Trans"
Let B="Soft"
Let C=%%A%%%%B%%
This would give C the value of "TransSoft"
To access a variable from within a variable you have to use brackets, '[' and ']':
Let A="sS"
Let B="Tran[%%A%%]oft"
This will give B the value of "TransSoft". Another example is
NumVariable I
Let I=0
:NextValue
Let I=I+1
if %%I%% <= %%ParamCount%% then
Let A=%%Param[%%I%%]%%
Message "Parameter %%I%% is %%A%%"
endif
if %%I%% < %%ParamCount%% then
Goto NextValue
endif