Hi all, please advise as I m a complete idiot to plants...

Few months back, I bought a pot of orchid w/o knowing how it will look like as no flowers have open yet.

After a while they bloom and it turns out to be Dendrobium Jade. the color is very nice and everyone in my family loves it.

A month ago, most of the flowers have faded so i decided to cut off all 3 flowers stalks/ stems.

Now my questions is

1. how to rebloom it?
2. Is there a standard length of how much i can cut off the stems? (i only cut it off with a slanted angle.)
3. is it true i must apply candle wax or other solution to the cut off stem?

pls advise as i have 4 more old orchids n they have not bloom for the last 2 years....

thks for yr efforts to read my questions.