、。
Right now, I'm in the middle of training for the day of my departure.
Literal
Just-now, I [topic-は] departure [genitive-の] day [toward-に向けて] training-in-middle is.
A slightly old-fashioned, earnest register. 只今 (ただいま) here is the formal 'right now, at this moment' — the same word used for 'I'm home' on entering a house, but used as a temporal adverb in written/formal speech. 旅立ち is a noun for 'setting out on a journey,' literary in feel, often used metaphorically for a life transition (graduation, leaving home). 修業 is 'training / study of a discipline,' distinct from ordinary 勉強; it implies apprenticeship, martial arts training, or sustained craft practice — note it is spelled 修業, not 修行 (which has a more religious/ascetic sense). ~に向けて ('heading toward,' 'with X in view') aims the training at a future date.