Your background in BASIC would be quite useful for using the T100MD+ PLC. The ladder logic requirement is mainly for logic or sequencing and most of the sophiscated computation such as temperature measurement, analog, math etc are all handled in TBASIC which is quite similar to many standard BASIC language.
To brush up some fundamental concept for ladder logic, you can start with some sample programs in the "\TRiLOGI\TL6\usr\samples\ladderexamples.pc6" folder. Use the i-TRiLOGI simulator to help you understand the concept by experimenting with the sample program.
A website
www.plcs.net also provide some useful fundamental knowledge of ladder logic.
Good luck and happy programming!