HELP! Thetford RV Toilet Question

Hi Everyone!

I am new to RVing and desperately need help with the toilet in my travel trailer (literally this is the first week in the trailer). I am not mechanically inclined so please, if you offer advice, tell me in simple terms, lol!

Forest River Flagstaff Super Lite TT
Thetford Toilet with the handle in the back of the toilet

Problem

1. No water comes into the bowl at all, have to add water manually
2. HORRIBLE SMELL comes from inside the toilet as soon as you flush, and I mean like, gag you and make you want to vomit smell!

Please help!

Thanks in advance!