When you come with train in Surin ,you can take a taxi or bus to Jharad.
Its about 1 hour driving with taxi from Surin to Jharad .
When you come with bus from Bangkok you can take the bus to Shangkha, en then you can take tuk-tuk (1 hour) or taxi to Jharad ‘½ hour) for about 500 THB.
I proposal to take VIP bus or bus NR.1 these are comfortable