TROUBLE WRITING THE START (ALREADY WROTE)

How do I explain this, my original starting starts with the MC having a dream (common I know that's why I wanted to change it) but the dream plays an important role in the story and is the reason behind all the MC's trauma's that are still happening in the present. My new idea is that it jumps straight to one of the problems but before the reader knows what happened it switches to like.
E.g A FEW MONTHS LATER
But I don’t think saying that would be good so I have no idea how I would pursue that idea, but if I did I would then make my MC write in his journal which plays an important role, Aswell. But all together I have many plot holes still but I’m just asking because I’m still on my first draft. Any ideas?