Well, you don't technically need a trade ticket, in this case. If you look at at API, it actually creates the Trade ticket on Tradier website. You have to execute the trade ticket on their website.
When the user clicks the trade button on an option spread, it simply opens the Tradier website with a populated trade ticket based on the parameters sent.
From the example on their website
https://dash.tradier.com/tradelink?
class=multileg&symbol=AAPL&
option_symbol[0]=AAPL220617C00270000&side[0]=buy_to_open&quantity[0]=1&
option_symbol[1]=AAPL220617C00280000&side[1]=buy_to_close&quantity[1]=2&
option_symbol[2]=AAPL220617P00240000&side[2]=sell_to_open&quantity[2]=3&
option_symbol[3]=AAPL220617P00250000&side[3]=sell_to_close&quantity[3]=4